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NWS Storm Prediction Center
SPC Sep 9, 2010 2000 UTC Day 1 Convective Outlook
SPC 2000Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0256 PM CDT THU SEP 09 2010 VALID 092000Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS INTO EARLY TONIGHT FOR THE NRN HIGH PLAINS... ...NRN HIGH PLAINS... NO CHANGES NEEDED AS OBJECTIVE ANALYSES SHOWED AIR MASS DESTABILIZING ACROSS WRN NEB/SD INTO SERN MT...ALONG AND E OF LEE TROUGH AND INVOF DEEPENING SURFACE LOW OVER SERN MT. EFFECTIVE BULK SHEAR IS STRENGTHENING /35-50 KT/ ACROSS THE CENTRAL/NRN HIGH PLAINS THIS AFTERNOON AS STRONGER JET CORE ATTENDANT TO ID SHORTWAVE TROUGH SPREADS NEWD. ...CENTRAL ND... ONGOING ELEVATED TSTMS /LOCATED N-E OF BIS/ MAY PRODUCE AN ISOLATED HAIL THREAT THIS AFTERNOON GIVEN EFFECTIVE BULK SHEAR /30-35 KT/... MARGINAL INSTABILITY AND MIDLEVEL LAPSE RATES NEAR 7 C/KM. THIS AREA CONTINUES TO WARRANT LOW SEVERE PROBABILITIES. ...CENTRAL/NRN AR... NO CHANGES NEEDED WITH THIS OUTLOOK MAINTAINING A LOW TORNADO PROBABILITY /2 PERCENT/ ACROSS NRN HALF OF AR...WITH GREATEST POTENTIAL...THOUGH STILL A LOW THREAT...ACROSS NWRN AR WHERE THE LOW LEVEL SW-NE ORIENTED CONFLUENCE ZONE INTERSECTS THE WARM FRONT. SUFFICIENT DEEP LAYER SHEAR SUPPORTING ORGANIZED STORMS RESIDES N/NE OF THE WARM FRONT WHICH EARLY THIS AFTERNOON EXTENDED FROM SWRN TN WNWWD THROUGH NRN AR TO A WEAKENING SURFACE LOW /ATTENDANT TO TC HERMINE/ OVER FAR SERN KS. HOWEVER...CURRENT LOW LEVEL EFFECTIVE SRH /200-300 M2 PER S2/ EXTENDING INTO NWRN AR INVOF THE WARM FRONT SUGGESTS A NON-ZERO TORNADO THREAT THROUGH THE AFTERNOON. FURTHER WEAKENING AND VEERING OF THE SWLY LLJ INTO WRN/NRN AR SHOULD REDUCE THIS LOW SEVERE WEATHER THREAT BY THIS EVENING. ...DOWNEAST MAINE... COLD MIDLEVEL TEMPERATURES...ATTENDANT TO CLOSED LOW MOVING ACROSS MAINE...COMBINED WITH SURFACE HEATING AND DEWPOINTS IN THE UPPER 50S HAS RESULTED IN MARGINAL INSTABILITY IN ADVANCE OF A WIND SHIFT. A FEW LIGHTNING STRIKES REMAIN POSSIBLE YET THIS AFTERNOON...PRIOR TO SURFACE BOUNDARY...WHICH CURRENTLY EXTENDED FROM NRN WASHINGTON TO LINCOLN COUNTIES...MOVES OFFSHORE. LIMITED POTENTIAL FOR STRIKES AND EXPECTED SHORT DURATION PRECLUDES THE INCLUSION OF A GENERAL TSTM AREA FOR THIS REGION. ..PETERS.. 09/09/2010 .PREV DISCUSSION... /ISSUED 1128 AM CDT THU SEP 09 2010/ ...NRN HIGH PLAINS THIS AFTERNOON INTO EARLY TONIGHT... NO SUBSTANTIAL CHANGES TO THE PRIOR OUTLOOK AREA AND REASONING. A HIGH-AMPLITUDE TROUGH WILL MOVE EWD FROM THE NRN ROCKIES/GREAT BASIN TO THE NRN HIGH PLAINS BY EARLY FRIDAY. THE MIDLEVEL TROUGH WILL BE PRECEDED BY A LEE CYCLONE THAT WILL DEVELOP NEWD FROM SE MT TO WRN ND...WHILE S OF THE CYCLONE A LEE TROUGH WILL MOVE SLOWLY EWD THIS EVENING ACROSS THE NRN AND CENTRAL HIGH PLAINS. BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S ARE RETURNING NNWWD IN A CORRIDOR FROM NEB TOWARD WRN ND TO THE E OF THE LEE TROUGH AND S OF A WARM FRONT...AND BENEATH A PLUME OF 7-7.5 C/KM MIDLEVEL LAPSE RATES. WITH ADDITIONAL SURFACE HEATING THROUGH THE AFTERNOON... MLCAPE VALUES WILL LIKELY INCREASE TO THE 1000-2000 J/KG RANGE... WITH MINIMAL CONVECTIVE INHIBITION BY LATE AFTERNOON ALONG THE LEE TROUGH. THUNDERSTORM DEVELOPMENT IS EXPECTED BY 21-23Z NEAR THE SURFACE LOW CLOSE TO THE MT/ND BORDER...AND SWD ALONG THE LEE TROUGH NEAR THE WY/SD BORDER. DEEP-LAYER VERTICAL SHEAR AND INSTABILITY WILL BE FAVORABLE FOR SUPERCELLS AND ORGANIZED LINE SEGMENTS...WITH AN ACCOMPANYING RISK FOR LARGE HAIL AND DAMAGING WINDS. A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE THIS EVENING...PRIMARILY ACROSS NW SD/SW ND IN PROXIMITY TO THE WARM FRONT WHERE THE INITIAL STORMS WILL BE SUPERCELLULAR AND SOMEWHAT STRONGER LOW-LEVEL SHEAR WILL CORRESPOND WITH THE LOW-LEVEL MOISTURE/INSTABILITY AXIS. THE SEVERE STORM THREAT WILL BEGIN TO DIMINISH TONIGHT TOWARD THE CENTRAL DAKOTAS. ...CENTRAL/NRN AR THIS AFTERNOON... THE REMNANTS OF TROPICAL DEPRESSION HERMINE ARE MOVING ENEWD FROM NE OK/SE KS TO NW AR AND SW MO...ALONG AND N OF SURFACE WARM FRONT NEAR I-40 ACROSS AR. SURFACE-BASED STORMS CAN BE EXPECTED NEAR THE INTERSECTION OF THE WARM FRONT AND THE PRIMARY CONFLUENCE BAND WHICH EXTENDS FROM SE OK INTO NW AR...WHICH ALSO COINCIDES WITH THE BELT OF STRONGER LOW-LEVEL SLY/SWLY FLOW AND EFFECTIVE SRH IN EXCESS OF 200 M2/S2. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW ROTATING STORMS THIS AFTERNOON...AND PERHAPS A BRIEF TORNADO ...ALONG THE WARM FRONT WITH THE REMNANTS OF HERMINE...BEFORE THE SYSTEM WEAKENS AND THE BOUNDARY LAYER STABILIZES BY LATE EVENING. AT THIS TIME...THE TORNADO THREAT APPEARS TO BE REDUCED A LITTLE FROM PRIOR DAYS...SO WILL MAINTAIN 2% TORNADO PROBABILITY AREA. Read more
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0256 PM CDT THU SEP 09 2010 VALID 092000Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS INTO EARLY TONIGHT FOR THE NRN HIGH PLAINS... ...NRN HIGH PLAINS... NO CHANGES NEEDED AS OBJECTIVE ANALYSES SHOWED AIR MASS DESTABILIZING ACROSS WRN NEB/SD INTO SERN MT...ALONG AND E OF LEE TROUGH AND INVOF DEEPENING SURFACE LOW OVER SERN MT. EFFECTIVE BULK SHEAR IS STRENGTHENING /35-50 KT/ ACROSS THE CENTRAL/NRN HIGH PLAINS THIS AFTERNOON AS STRONGER JET CORE ATTENDANT TO ID SHORTWAVE TROUGH SPREADS NEWD. ...CENTRAL ND... ONGOING ELEVATED TSTMS /LOCATED N-E OF BIS/ MAY PRODUCE AN ISOLATED HAIL THREAT THIS AFTERNOON GIVEN EFFECTIVE BULK SHEAR /30-35 KT/... MARGINAL INSTABILITY AND MIDLEVEL LAPSE RATES NEAR 7 C/KM. THIS AREA CONTINUES TO WARRANT LOW SEVERE PROBABILITIES. ...CENTRAL/NRN AR... NO CHANGES NEEDED WITH THIS OUTLOOK MAINTAINING A LOW TORNADO PROBABILITY /2 PERCENT/ ACROSS NRN HALF OF AR...WITH GREATEST POTENTIAL...THOUGH STILL A LOW THREAT...ACROSS NWRN AR WHERE THE LOW LEVEL SW-NE ORIENTED CONFLUENCE ZONE INTERSECTS THE WARM FRONT. SUFFICIENT DEEP LAYER SHEAR SUPPORTING ORGANIZED STORMS RESIDES N/NE OF THE WARM FRONT WHICH EARLY THIS AFTERNOON EXTENDED FROM SWRN TN WNWWD THROUGH NRN AR TO A WEAKENING SURFACE LOW /ATTENDANT TO TC HERMINE/ OVER FAR SERN KS. HOWEVER...CURRENT LOW LEVEL EFFECTIVE SRH /200-300 M2 PER S2/ EXTENDING INTO NWRN AR INVOF THE WARM FRONT SUGGESTS A NON-ZERO TORNADO THREAT THROUGH THE AFTERNOON. FURTHER WEAKENING AND VEERING OF THE SWLY LLJ INTO WRN/NRN AR SHOULD REDUCE THIS LOW SEVERE WEATHER THREAT BY THIS EVENING. ...DOWNEAST MAINE... COLD MIDLEVEL TEMPERATURES...ATTENDANT TO CLOSED LOW MOVING ACROSS MAINE...COMBINED WITH SURFACE HEATING AND DEWPOINTS IN THE UPPER 50S HAS RESULTED IN MARGINAL INSTABILITY IN ADVANCE OF A WIND SHIFT. A FEW LIGHTNING STRIKES REMAIN POSSIBLE YET THIS AFTERNOON...PRIOR TO SURFACE BOUNDARY...WHICH CURRENTLY EXTENDED FROM NRN WASHINGTON TO LINCOLN COUNTIES...MOVES OFFSHORE. LIMITED POTENTIAL FOR STRIKES AND EXPECTED SHORT DURATION PRECLUDES THE INCLUSION OF A GENERAL TSTM AREA FOR THIS REGION. ..PETERS.. 09/09/2010 .PREV DISCUSSION... /ISSUED 1128 AM CDT THU SEP 09 2010/ ...NRN HIGH PLAINS THIS AFTERNOON INTO EARLY TONIGHT... NO SUBSTANTIAL CHANGES TO THE PRIOR OUTLOOK AREA AND REASONING. A HIGH-AMPLITUDE TROUGH WILL MOVE EWD FROM THE NRN ROCKIES/GREAT BASIN TO THE NRN HIGH PLAINS BY EARLY FRIDAY. THE MIDLEVEL TROUGH WILL BE PRECEDED BY A LEE CYCLONE THAT WILL DEVELOP NEWD FROM SE MT TO WRN ND...WHILE S OF THE CYCLONE A LEE TROUGH WILL MOVE SLOWLY EWD THIS EVENING ACROSS THE NRN AND CENTRAL HIGH PLAINS. BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S ARE RETURNING NNWWD IN A CORRIDOR FROM NEB TOWARD WRN ND TO THE E OF THE LEE TROUGH AND S OF A WARM FRONT...AND BENEATH A PLUME OF 7-7.5 C/KM MIDLEVEL LAPSE RATES. WITH ADDITIONAL SURFACE HEATING THROUGH THE AFTERNOON... MLCAPE VALUES WILL LIKELY INCREASE TO THE 1000-2000 J/KG RANGE... WITH MINIMAL CONVECTIVE INHIBITION BY LATE AFTERNOON ALONG THE LEE TROUGH. THUNDERSTORM DEVELOPMENT IS EXPECTED BY 21-23Z NEAR THE SURFACE LOW CLOSE TO THE MT/ND BORDER...AND SWD ALONG THE LEE TROUGH NEAR THE WY/SD BORDER. DEEP-LAYER VERTICAL SHEAR AND INSTABILITY WILL BE FAVORABLE FOR SUPERCELLS AND ORGANIZED LINE SEGMENTS...WITH AN ACCOMPANYING RISK FOR LARGE HAIL AND DAMAGING WINDS. A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE THIS EVENING...PRIMARILY ACROSS NW SD/SW ND IN PROXIMITY TO THE WARM FRONT WHERE THE INITIAL STORMS WILL BE SUPERCELLULAR AND SOMEWHAT STRONGER LOW-LEVEL SHEAR WILL CORRESPOND WITH THE LOW-LEVEL MOISTURE/INSTABILITY AXIS. THE SEVERE STORM THREAT WILL BEGIN TO DIMINISH TONIGHT TOWARD THE CENTRAL DAKOTAS. ...CENTRAL/NRN AR THIS AFTERNOON... THE REMNANTS OF TROPICAL DEPRESSION HERMINE ARE MOVING ENEWD FROM NE OK/SE KS TO NW AR AND SW MO...ALONG AND N OF SURFACE WARM FRONT NEAR I-40 ACROSS AR. SURFACE-BASED STORMS CAN BE EXPECTED NEAR THE INTERSECTION OF THE WARM FRONT AND THE PRIMARY CONFLUENCE BAND WHICH EXTENDS FROM SE OK INTO NW AR...WHICH ALSO COINCIDES WITH THE BELT OF STRONGER LOW-LEVEL SLY/SWLY FLOW AND EFFECTIVE SRH IN EXCESS OF 200 M2/S2. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW ROTATING STORMS THIS AFTERNOON...AND PERHAPS A BRIEF TORNADO ...ALONG THE WARM FRONT WITH THE REMNANTS OF HERMINE...BEFORE THE SYSTEM WEAKENS AND THE BOUNDARY LAYER STABILIZES BY LATE EVENING. AT THIS TIME...THE TORNADO THREAT APPEARS TO BE REDUCED A LITTLE FROM PRIOR DAYS...SO WILL MAINTAIN 2% TORNADO PROBABILITY AREA. Read more
Categories: Weather
SPC Sep 9, 2010 2000 UTC Day 1 Convective Outlook
SPC 2000Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0256 PM CDT THU SEP 09 2010 VALID 092000Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS INTO EARLY TONIGHT FOR THE NRN HIGH PLAINS... ...NRN HIGH PLAINS... NO CHANGES NEEDED AS OBJECTIVE ANALYSES SHOWED AIR MASS DESTABILIZING ACROSS WRN NEB/SD INTO SERN MT...ALONG AND E OF LEE TROUGH AND INVOF DEEPENING SURFACE LOW OVER SERN MT. EFFECTIVE BULK SHEAR IS STRENGTHENING /35-50 KT/ ACROSS THE CENTRAL/NRN HIGH PLAINS THIS AFTERNOON AS STRONGER JET CORE ATTENDANT TO ID SHORTWAVE TROUGH SPREADS NEWD. ...CENTRAL ND... ONGOING ELEVATED TSTMS /LOCATED N-E OF BIS/ MAY PRODUCE AN ISOLATED HAIL THREAT THIS AFTERNOON GIVEN EFFECTIVE BULK SHEAR /30-35 KT/... MARGINAL INSTABILITY AND MIDLEVEL LAPSE RATES NEAR 7 C/KM. THIS AREA CONTINUES TO WARRANT LOW SEVERE PROBABILITIES. ...CENTRAL/NRN AR... NO CHANGES NEEDED WITH THIS OUTLOOK MAINTAINING A LOW TORNADO PROBABILITY /2 PERCENT/ ACROSS NRN HALF OF AR...WITH GREATEST POTENTIAL...THOUGH STILL A LOW THREAT...ACROSS NWRN AR WHERE THE LOW LEVEL SW-NE ORIENTED CONFLUENCE ZONE INTERSECTS THE WARM FRONT. SUFFICIENT DEEP LAYER SHEAR SUPPORTING ORGANIZED STORMS RESIDES N/NE OF THE WARM FRONT WHICH EARLY THIS AFTERNOON EXTENDED FROM SWRN TN WNWWD THROUGH NRN AR TO A WEAKENING SURFACE LOW /ATTENDANT TO TC HERMINE/ OVER FAR SERN KS. HOWEVER...CURRENT LOW LEVEL EFFECTIVE SRH /200-300 M2 PER S2/ EXTENDING INTO NWRN AR INVOF THE WARM FRONT SUGGESTS A NON-ZERO TORNADO THREAT THROUGH THE AFTERNOON. FURTHER WEAKENING AND VEERING OF THE SWLY LLJ INTO WRN/NRN AR SHOULD REDUCE THIS LOW SEVERE WEATHER THREAT BY THIS EVENING. ...DOWNEAST MAINE... COLD MIDLEVEL TEMPERATURES...ATTENDANT TO CLOSED LOW MOVING ACROSS MAINE...COMBINED WITH SURFACE HEATING AND DEWPOINTS IN THE UPPER 50S HAS RESULTED IN MARGINAL INSTABILITY IN ADVANCE OF A WIND SHIFT. A FEW LIGHTNING STRIKES REMAIN POSSIBLE YET THIS AFTERNOON...PRIOR TO SURFACE BOUNDARY...WHICH CURRENTLY EXTENDED FROM NRN WASHINGTON TO LINCOLN COUNTIES...MOVES OFFSHORE. LIMITED POTENTIAL FOR STRIKES AND EXPECTED SHORT DURATION PRECLUDES THE INCLUSION OF A GENERAL TSTM AREA FOR THIS REGION. ..PETERS.. 09/09/2010 .PREV DISCUSSION... /ISSUED 1128 AM CDT THU SEP 09 2010/ ...NRN HIGH PLAINS THIS AFTERNOON INTO EARLY TONIGHT... NO SUBSTANTIAL CHANGES TO THE PRIOR OUTLOOK AREA AND REASONING. A HIGH-AMPLITUDE TROUGH WILL MOVE EWD FROM THE NRN ROCKIES/GREAT BASIN TO THE NRN HIGH PLAINS BY EARLY FRIDAY. THE MIDLEVEL TROUGH WILL BE PRECEDED BY A LEE CYCLONE THAT WILL DEVELOP NEWD FROM SE MT TO WRN ND...WHILE S OF THE CYCLONE A LEE TROUGH WILL MOVE SLOWLY EWD THIS EVENING ACROSS THE NRN AND CENTRAL HIGH PLAINS. BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S ARE RETURNING NNWWD IN A CORRIDOR FROM NEB TOWARD WRN ND TO THE E OF THE LEE TROUGH AND S OF A WARM FRONT...AND BENEATH A PLUME OF 7-7.5 C/KM MIDLEVEL LAPSE RATES. WITH ADDITIONAL SURFACE HEATING THROUGH THE AFTERNOON... MLCAPE VALUES WILL LIKELY INCREASE TO THE 1000-2000 J/KG RANGE... WITH MINIMAL CONVECTIVE INHIBITION BY LATE AFTERNOON ALONG THE LEE TROUGH. THUNDERSTORM DEVELOPMENT IS EXPECTED BY 21-23Z NEAR THE SURFACE LOW CLOSE TO THE MT/ND BORDER...AND SWD ALONG THE LEE TROUGH NEAR THE WY/SD BORDER. DEEP-LAYER VERTICAL SHEAR AND INSTABILITY WILL BE FAVORABLE FOR SUPERCELLS AND ORGANIZED LINE SEGMENTS...WITH AN ACCOMPANYING RISK FOR LARGE HAIL AND DAMAGING WINDS. A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE THIS EVENING...PRIMARILY ACROSS NW SD/SW ND IN PROXIMITY TO THE WARM FRONT WHERE THE INITIAL STORMS WILL BE SUPERCELLULAR AND SOMEWHAT STRONGER LOW-LEVEL SHEAR WILL CORRESPOND WITH THE LOW-LEVEL MOISTURE/INSTABILITY AXIS. THE SEVERE STORM THREAT WILL BEGIN TO DIMINISH TONIGHT TOWARD THE CENTRAL DAKOTAS. ...CENTRAL/NRN AR THIS AFTERNOON... THE REMNANTS OF TROPICAL DEPRESSION HERMINE ARE MOVING ENEWD FROM NE OK/SE KS TO NW AR AND SW MO...ALONG AND N OF SURFACE WARM FRONT NEAR I-40 ACROSS AR. SURFACE-BASED STORMS CAN BE EXPECTED NEAR THE INTERSECTION OF THE WARM FRONT AND THE PRIMARY CONFLUENCE BAND WHICH EXTENDS FROM SE OK INTO NW AR...WHICH ALSO COINCIDES WITH THE BELT OF STRONGER LOW-LEVEL SLY/SWLY FLOW AND EFFECTIVE SRH IN EXCESS OF 200 M2/S2. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW ROTATING STORMS THIS AFTERNOON...AND PERHAPS A BRIEF TORNADO ...ALONG THE WARM FRONT WITH THE REMNANTS OF HERMINE...BEFORE THE SYSTEM WEAKENS AND THE BOUNDARY LAYER STABILIZES BY LATE EVENING. AT THIS TIME...THE TORNADO THREAT APPEARS TO BE REDUCED A LITTLE FROM PRIOR DAYS...SO WILL MAINTAIN 2% TORNADO PROBABILITY AREA. Read more
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0256 PM CDT THU SEP 09 2010 VALID 092000Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS INTO EARLY TONIGHT FOR THE NRN HIGH PLAINS... ...NRN HIGH PLAINS... NO CHANGES NEEDED AS OBJECTIVE ANALYSES SHOWED AIR MASS DESTABILIZING ACROSS WRN NEB/SD INTO SERN MT...ALONG AND E OF LEE TROUGH AND INVOF DEEPENING SURFACE LOW OVER SERN MT. EFFECTIVE BULK SHEAR IS STRENGTHENING /35-50 KT/ ACROSS THE CENTRAL/NRN HIGH PLAINS THIS AFTERNOON AS STRONGER JET CORE ATTENDANT TO ID SHORTWAVE TROUGH SPREADS NEWD. ...CENTRAL ND... ONGOING ELEVATED TSTMS /LOCATED N-E OF BIS/ MAY PRODUCE AN ISOLATED HAIL THREAT THIS AFTERNOON GIVEN EFFECTIVE BULK SHEAR /30-35 KT/... MARGINAL INSTABILITY AND MIDLEVEL LAPSE RATES NEAR 7 C/KM. THIS AREA CONTINUES TO WARRANT LOW SEVERE PROBABILITIES. ...CENTRAL/NRN AR... NO CHANGES NEEDED WITH THIS OUTLOOK MAINTAINING A LOW TORNADO PROBABILITY /2 PERCENT/ ACROSS NRN HALF OF AR...WITH GREATEST POTENTIAL...THOUGH STILL A LOW THREAT...ACROSS NWRN AR WHERE THE LOW LEVEL SW-NE ORIENTED CONFLUENCE ZONE INTERSECTS THE WARM FRONT. SUFFICIENT DEEP LAYER SHEAR SUPPORTING ORGANIZED STORMS RESIDES N/NE OF THE WARM FRONT WHICH EARLY THIS AFTERNOON EXTENDED FROM SWRN TN WNWWD THROUGH NRN AR TO A WEAKENING SURFACE LOW /ATTENDANT TO TC HERMINE/ OVER FAR SERN KS. HOWEVER...CURRENT LOW LEVEL EFFECTIVE SRH /200-300 M2 PER S2/ EXTENDING INTO NWRN AR INVOF THE WARM FRONT SUGGESTS A NON-ZERO TORNADO THREAT THROUGH THE AFTERNOON. FURTHER WEAKENING AND VEERING OF THE SWLY LLJ INTO WRN/NRN AR SHOULD REDUCE THIS LOW SEVERE WEATHER THREAT BY THIS EVENING. ...DOWNEAST MAINE... COLD MIDLEVEL TEMPERATURES...ATTENDANT TO CLOSED LOW MOVING ACROSS MAINE...COMBINED WITH SURFACE HEATING AND DEWPOINTS IN THE UPPER 50S HAS RESULTED IN MARGINAL INSTABILITY IN ADVANCE OF A WIND SHIFT. A FEW LIGHTNING STRIKES REMAIN POSSIBLE YET THIS AFTERNOON...PRIOR TO SURFACE BOUNDARY...WHICH CURRENTLY EXTENDED FROM NRN WASHINGTON TO LINCOLN COUNTIES...MOVES OFFSHORE. LIMITED POTENTIAL FOR STRIKES AND EXPECTED SHORT DURATION PRECLUDES THE INCLUSION OF A GENERAL TSTM AREA FOR THIS REGION. ..PETERS.. 09/09/2010 .PREV DISCUSSION... /ISSUED 1128 AM CDT THU SEP 09 2010/ ...NRN HIGH PLAINS THIS AFTERNOON INTO EARLY TONIGHT... NO SUBSTANTIAL CHANGES TO THE PRIOR OUTLOOK AREA AND REASONING. A HIGH-AMPLITUDE TROUGH WILL MOVE EWD FROM THE NRN ROCKIES/GREAT BASIN TO THE NRN HIGH PLAINS BY EARLY FRIDAY. THE MIDLEVEL TROUGH WILL BE PRECEDED BY A LEE CYCLONE THAT WILL DEVELOP NEWD FROM SE MT TO WRN ND...WHILE S OF THE CYCLONE A LEE TROUGH WILL MOVE SLOWLY EWD THIS EVENING ACROSS THE NRN AND CENTRAL HIGH PLAINS. BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S ARE RETURNING NNWWD IN A CORRIDOR FROM NEB TOWARD WRN ND TO THE E OF THE LEE TROUGH AND S OF A WARM FRONT...AND BENEATH A PLUME OF 7-7.5 C/KM MIDLEVEL LAPSE RATES. WITH ADDITIONAL SURFACE HEATING THROUGH THE AFTERNOON... MLCAPE VALUES WILL LIKELY INCREASE TO THE 1000-2000 J/KG RANGE... WITH MINIMAL CONVECTIVE INHIBITION BY LATE AFTERNOON ALONG THE LEE TROUGH. THUNDERSTORM DEVELOPMENT IS EXPECTED BY 21-23Z NEAR THE SURFACE LOW CLOSE TO THE MT/ND BORDER...AND SWD ALONG THE LEE TROUGH NEAR THE WY/SD BORDER. DEEP-LAYER VERTICAL SHEAR AND INSTABILITY WILL BE FAVORABLE FOR SUPERCELLS AND ORGANIZED LINE SEGMENTS...WITH AN ACCOMPANYING RISK FOR LARGE HAIL AND DAMAGING WINDS. A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE THIS EVENING...PRIMARILY ACROSS NW SD/SW ND IN PROXIMITY TO THE WARM FRONT WHERE THE INITIAL STORMS WILL BE SUPERCELLULAR AND SOMEWHAT STRONGER LOW-LEVEL SHEAR WILL CORRESPOND WITH THE LOW-LEVEL MOISTURE/INSTABILITY AXIS. THE SEVERE STORM THREAT WILL BEGIN TO DIMINISH TONIGHT TOWARD THE CENTRAL DAKOTAS. ...CENTRAL/NRN AR THIS AFTERNOON... THE REMNANTS OF TROPICAL DEPRESSION HERMINE ARE MOVING ENEWD FROM NE OK/SE KS TO NW AR AND SW MO...ALONG AND N OF SURFACE WARM FRONT NEAR I-40 ACROSS AR. SURFACE-BASED STORMS CAN BE EXPECTED NEAR THE INTERSECTION OF THE WARM FRONT AND THE PRIMARY CONFLUENCE BAND WHICH EXTENDS FROM SE OK INTO NW AR...WHICH ALSO COINCIDES WITH THE BELT OF STRONGER LOW-LEVEL SLY/SWLY FLOW AND EFFECTIVE SRH IN EXCESS OF 200 M2/S2. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW ROTATING STORMS THIS AFTERNOON...AND PERHAPS A BRIEF TORNADO ...ALONG THE WARM FRONT WITH THE REMNANTS OF HERMINE...BEFORE THE SYSTEM WEAKENS AND THE BOUNDARY LAYER STABILIZES BY LATE EVENING. AT THIS TIME...THE TORNADO THREAT APPEARS TO BE REDUCED A LITTLE FROM PRIOR DAYS...SO WILL MAINTAIN 2% TORNADO PROBABILITY AREA. Read more
Categories: Weather
SPC Day 3-8 Fire Weather Outlook
SPC Day 3-8 Fire Weather Outlook
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 3-8 Fire Weather Outlook
SPC Day 3-8 Fire Weather Outlook
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 3-8 Fire Weather Outlook
SPC Day 3-8 Fire Weather Outlook
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 3-8 Fire Weather Outlook
SPC Day 3-8 Fire Weather Outlook
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 3-8 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 PM CDT THU SEP 09 2010 VALID 111200Z - 171200Z A GENERALLY LOW AMPLITUDE UPPER LEVEL FLOW REGIME IS FORECAST TO PERSIST THROUGH MOST OF THE D3-8 PERIOD. THERE MAY BE A LOW POTENTIAL FOR NEAR CRITICAL FIRE WEATHER CONDITIONS OVER THE MID ATLANTIC REGION ON TUESDAY/D6 BASED ON GFS AND MREF MODEL GUIDANCE. HOWEVER...THE PROBABILITY APPEARS TO BE TOO LOW ATTM TO SUPPORT AN OUTLOOK AREA. ..GARNER.. 09/09/2010 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 2 Fire Weather Outlook
SPC Day 2 Fire Weather Outlook
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 2 Fire Weather Outlook
SPC Day 2 Fire Weather Outlook
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 2 Fire Weather Outlook
SPC Day 2 Fire Weather Outlook
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 2 Fire Weather Outlook
SPC Day 2 Fire Weather Outlook
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0141 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... A MID-LEVEL SHORTWAVE TROUGH /AND ASSOCIATED MODERATE WLY WIND FIELDS...AROUND 20 KT OF 700 MB FLOW OVER N-CNTRL CO TO 35 KT OVER SERN WY/ IS FORECAST TO PASS ACROSS THE CNTRL ROCKIES BY 18Z FRIDAY...AND WILL PROMOTE MODEST DOWNSLOPE WINDS ALONG THE LEE OF THE ROCKIES/FOOTHILLS IN N-CNTRL CO /WHERE ONGOING WILDFIRES ARE OCCURRING/. 12Z NAM CONTINUES TO BE MOST BULLISH WITH THE DEVELOPMENT OF 20 MPH SUSTAINED WIND SPEEDS OVER N-CNTRL CO...WITH A PERIOD OF NEAR CRITICAL RH VALUES EVIDENT AT 12Z /ASSOCIATED WITH STRONGER OVERNIGHT DOWNSLOPE WINDS/...AND A SECOND PERIOD OF CRITICAL RH VALUES OCCURRING NEAR 18Z /WHICH WILL BE MORE DIURNALLY DRIVEN/. GIVEN THE ONGOING FOUR MILE CANYON FIRE...CRITICAL AREA WILL BE MAINTAINED. FARTHER N OVER SERN WY AND THE SWRN NEB PANHANDLE...LOCAL MAXIMA IN SFC-700 MB WLY FLOW IS OBSERVED IN LATEST MODEL GUIDANCE...WHICH MAY FAVOR ENHANCED WARMING/DRYING BOUNDARY LAYER PROFILES DUE TO STRONG DOWNSLOPE REGIME...YIELDING POSSIBLE CRITICAL FIRE WEATHER CONDITIONS WITH SUSTAINED WIND SPEEDS OF 20-25 MPH AND GUSTS AOA 30 MPH. ...E-CNTRL NM AND FAR W TX... MODEL GUIDANCE CONTINUES TO DEPICT A ZONE OF 30 KT 700 MB FLOW /AS DISCUSSED IN PREVIOUS D2 FORECAST/ RESIDING OVER E-CNTRL NM AS WELL AS FAR W TX...WHICH MAY PROMOTE 15-20 MPH SUSTAINED WLY WIND SPEEDS AT THE SURFACE AS STRONG HEATING AND BOUNDARY LAYER MIXING TAKES PLACE. WITH MIN RH VALUES AROUND 10 PERCENT...NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0453 AM CDT THU SEP 09 2010/ ...SYNOPSIS... AN UPPER-LEVEL SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS WILL SHIFT E/NEWD ACROSS THE SRN CANADIAN PRAIRIE PROVINCES AND THE NRN PLAINS. PRIMARY SURFACE CYCLONE WILL MOVE NWD AND OCCLUDE ACROSS SRN MANITOBA...WHILE AN ATTENDANT COLD FRONT PROGRESSES EWD ACROSS THE NRN/CNTRL PLAINS. ...FAR SERN WY/N-CNTRL CO/SWRN NEB PANHANDLE... MARGINAL TO LOCALIZED LOW-END CRITICAL CONDITIONS SHOULD DEVELOP FRI ALONG THE LEE OF THE FRONT RANGE IN SERN WY/N-CNTRL CO EWD INTO THE NEB PANHANDLE. LOCALLY GUSTY WLY WINDS MAY BE ONGOING AT 12Z/FRI ACROSS THE FOOTHILLS. THE 06Z NAM REMAINS THE MOST BULLISH OPERATIONAL MODEL IN TEMPORAL EXTENT AND MAGNITUDE OF LOW-LEVEL FLOW LATE DAY 1. HOWEVER...IT DOES DEPICT AT LEAST FAIR RH RECOVERY OCCURRING FRI MORNING WHICH SUGGESTS THE PROBABILITY OF ONGOING CRITICAL CONDITIONS TO BE LOW. AS DAYTIME HEATING ENSUES...A DEEPENING MIXED BOUNDARY LAYER WILL POTENTIALLY SUPPORT MORE WIDESPREAD GUSTS TO REACH THE SURFACE. NEVERTHELESS...CONSENSUS OF MODEL GUIDANCE INDICATES LOW/MID-LEVEL FLOW WILL WEAKEN THROUGH THE DAY. SUSTAINED SURFACE WINDS SHOULD AVERAGE AROUND 15 TO 20 MPH WITH GUSTS OF 30 TO 40 MPH ACROSS SERN WY INTO NEB PANHANDLE AND EXTREME NRN CO...WHERE AFTERNOON RH VALUES SHOULD BECOME MARGINALLY LOW /FROM 15 TO 20 PERCENT/. FARTHER S IN N-CNTRL CO...SUSTAINED WINDS SHOULD BE MODERATE AROUND 15 MPH WITH RH VALUES NEAR 15 PERCENT. ...E-CNTRL NM... LATEST MODEL FORECASTS ARE HIGHLY CONSISTENT THAT A ZONE OF ENHANCED LOW-LEVEL WLYS /AROUND 30 TO 35 MPH AT 700 MB/ WILL DEVELOP BETWEEN THE SANGRE DE CRISTO AND SACRAMENTO MTNS FRI MORNING. AS DAYTIME HEATING COMMENCES...MIXING OF THIS MODERATELY STRONG FLOW TO THE SURFACE WILL SUPPORT SUSTAINED WINDS AROUND 15 TO 20 MPH BY EARLY AFTERNOON. THIS WILL BE JUXTAPOSED WITH RH VALUES FALLING TO BETWEEN 8 AND 15 PERCENT...LIKELY RESULTING IN AN ENHANCED TO LOCALIZED CRITICAL THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC - No MDs are in effect as of Thu Sep 9 18:43:01 UTC 2010
No Mesoscale Discussions are in effect as of Thu Sep 9 18:43:01 UTC 2010.
Categories: Weather
SPC Sep 9, 2010 1730 UTC Day 2 Convective Outlook
SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
Categories: Weather
SPC Sep 9, 2010 1730 UTC Day 2 Convective Outlook
SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
Categories: Weather
SPC Sep 9, 2010 1730 UTC Day 2 Convective Outlook
SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
Categories: Weather
SPC Sep 9, 2010 1730 UTC Day 2 Convective Outlook
SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1223 PM CDT THU SEP 09 2010 VALID 101200Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO VALLEY AND SOUTH CENTRAL PLAINS FRIDAY AFTERNOON AND EVENING... ...SYNOPSIS... LATE MORNING WATER VAPOR IMAGERY SHOWED A COUPLE OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WRN TROUGH...1/ MOVING NEWD THROUGH NRN GREAT BASIN...AND 2/ MOVING SEWD THROUGH ORE. DURING DAY 2...THE LEAD SHORTWAVE TROUGH WILL LIFT NNEWD INTO CENTRAL CANADA EARLY IN THE PERIOD...WHILE THE ORE SHORTWAVE TRACKS ENEWD FROM THE NRN GREAT BASIN TO THE DAKOTAS BY 11/00Z AND INTO THE UPPER MS VALLEY BY 12Z SATURDAY...AIDING IN THE EWD ADVANCEMENT OF THE WRN LONGWAVE TROUGH. AN ASSOCIATED EAST-SOUTHEAST ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS. MEANWHILE...A SURFACE BOUNDARY EXTENDING EWD FROM AN AREA OF LOW PRESSURE IN WRN KS INTO CENTRAL MO TO LOWER TN VALLEY WILL SHIFT NWD INTO LOWER MO VALLEY BY FRIDAY AFTERNOON PROVIDING FOCUS FOR ADDITIONAL STORMS. ...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS... STRONGEST HEIGHT FALLS ARE EXPECTED ACROSS THE NRN PLAINS TO UPPER MS VALLEY THIS FORECAST PERIOD...WITH WEAKER FALLS /30-40 METER PER 12 HR AT 500 MB/ OCCURRING FARTHER S ACROSS THE LOWER MO VALLEY AFTER 11/00Z. EXTENSIVE CLOUD COVER IS EXPECTED ON THE COOL SIDE /E AND N/ OF THE AFOREMENTIONED SURFACE BOUNDARIES FROM THE MID MO TO MID MS VALLEYS. THIS FACTOR WILL TEND TO LIMIT THE NWD MOVEMENT OF THE WARM FRONT WITH STRONGEST SURFACE HEATING LIKELY OCCURRING ACROSS THE ERN KS/SWRN MO PORTION OF THE SLIGHT RISK AREA. INCREASING LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ ACROSS THE WARM SECTOR WILL SUPPORT MODERATE-STRONG INSTABILITY /MLCAPE 2000-3000 J PER KG/. A DRY LINE EXTENDING SWD FROM THE KS LOW AND THE SEWD ADVANCING COLD FRONT WILL PROVIDE THE FOCI FOR CONVECTION/TSTMS FRIDAY AFTERNOON...ESPECIALLY AS THE COLD FRONT MERGES WITH/OVERTAKES THE DRY LINE. THIS PROCESS SHOULD OCCUR INITIALLY OVER NERN-ERN KS AT THE TRIPLE POINT...AND THEN SSWWD INTO OK FRIDAY EVENING/ NIGHT. ADDITIONAL STORMS WILL BE POSSIBLE WITHIN LOW LEVEL WAA REGIME ALONG WARM FRONT IN MO. ALTHOUGH STRONGER MID-UPPER LEVEL WINDS ARE EXPECTED TO LAG THE COLD FRONT...SOME INCREASE IN WSWLY MIDLEVEL WINDS ACROSS THE SLIGHT RISK AREA COMBINED WITH VERTICALLY VEERING WIND PROFILES SUGGESTS EFFECTIVE BULK SHEAR WILL BE AROUND 40 KT. THIS IS FAVORABLE FOR SUPERCELLS WITH A THREAT FOR STRONG/DAMAGING WINDS...HAIL AND A TORNADO OR TWO... ESPECIALLY WITH THE INITIAL ACTIVITY. MODELS SUGGEST STORMS COULD EVOLVE INTO A LINEAR MCS INTO THE EVENING AS GREATER HEIGHT FALLS SPREAD INTO THE LOWER MO VALLEY...AND ACTIVITY BACKBUILDS SSWWD INTO OK. THE SLIGHT RISK AREA HAS BEEN EXPANDED SWD INTO NRN OK...WHERE STRONG INSTABILITY WILL PROMOTE THE POTENTIAL FOR SEVERE STORMS AS THE COLD FRONT ADVANCES SEWD INTO THAT REGION BY EARLY EVENING...PRIOR TO THE ONSET OF BOUNDARY LAYER STABILIZATION. ...ERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST... A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH ORIENTED OCCLUDING FRONTAL ZONE...WHERE MOISTURE CORRIDOR SHOULD BE RATHER NARROW AND LOCATED INVOF THE FRONT. NONETHELESS...A FEW EARLY DAY ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/ MAY OCCUR ALONG THE FRONT DURING THE AFTERNOON ACROSS THE ERN DAKOTAS AS STRONGER FORCING FOR ASCENT SPREADS INTO THIS REGION WITH THE APPROACH OF NRN GREAT BASIN SHORTWAVE TROUGH. GIVEN WEAK INSTABILITY...OVERALL SEVERE WEATHER THREAT CONTINUES TO APPEAR TOO ISOLATED TO WARRANT THE INCLUSION OF A CATEGORICAL SLIGHT RISK AREA. STORMS THAT DO FORM SHOULD TEND TO BE LINE SEGMENTS...GIVEN EFFECTIVE BULK SHEAR UP TO 40 KT ORIENTED NEARLY PARALLEL TO THE OCCLUDING FRONT. ..PETERS.. 09/09/2010 Read more
Categories: Weather
SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 AM CDT THU SEP 09 2010 VALID 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WY...NWRN/N-CNTRL CO... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NERN AZ...FOUR CORNERS... ...PORTIONS OF WY...NWRN/N-CNTRL CO... SATELLITE IMAGERY AT 15Z SHOWS A SHORTWAVE TROUGH PROGRESSING NEWD ACROSS THE GREAT BASIN...AND LATEST MODEL GUIDANCE INDICATES IT WILL CONTINUE ITS NEWD TREK ACROSS WY DURING THE MID TO LATE AFTERNOON. STRONG LOW TO MID LEVEL SWLY WIND FIELDS WILL ACCOMPANY THIS UPPER LEVEL FEATURE...FAVORING SUSTAINED SURFACE SPEEDS UP TO 35 MPH AND GUSTS OF 40-60 MPH OVER CNTRL AND SRN WY. MODIFIED 12Z RAOBS AND MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE SOMEWHAT MARGINAL AFTERNOON RH VALUES. HOWEVER...THE STRENGTH OF THE WIND FIELDS ARE EXPECTED TO COMPENSATE. FARTHER S ALONG THE FOOTHILLS OF THE FRONT RANGE...NAM FORECAST SOUNDINGS CONTINUE TO INDICATE AN INCREASE IN WLY WINDS IMMEDIATELY ABOVE THE SURFACE BY 06Z/FRIDAY...WHICH SUPPORTS THE EXTENSION OF THE CRITICAL AREA MADE IN THE PREVIOUS FORECAST. THEREFORE...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF NERN AZ...FOUR CORNERS... NO CHANGES MADE TO THE PREVIOUS FORECAST. ...CNTRL/ERN MD...DE...NERN VA...D.C.... PREVIOUS FORECAST DISCUSSION APPEARS TO BE ON TRACK...NO CHANGES HAVE BEEN MADE. ...PORTIONS OF CNTRL/S-CNTRL CO... AS SWLY MID/UPPER-LEVEL FLOW INCREASES ACROSS THE REGION TODAY...SUSTAINED SURFACE WIND SPEEDS OF 15-20 MPH ARE LIKELY TO DEVELOP. WARM/DEEPLY MIXED BOUNDARY LAYER PROFILES ARE EVIDENT IN MODEL FORECAST SOUNDINGS...AND AFTERNOON RH VALUES AROUND 10 PERCENT WILL BE POSSIBLE. DURING THE OVERNIGHT...WLY WIND SPEEDS ARE FORECAST TO INCREASE FURTHER /AROUND 30-40 KT AT 1 KM AGL/ INVOF THE FRONT RANGE/ADJACENT FOOTHILLS AS A MID-LEVEL SHORTWAVE TROUGH BEGINS TO APPROACH THE REGION...WHICH MAY PROMOTE LOCALLY GUSTY WINDS AND POOR OVERNIGHT RH RECOVERY. ..GARNER.. 09/09/2010 .PREV DISCUSSION... /ISSUED 0343 AM CDT THU SEP 09 2010/ ...SYNOPSIS... A POTENT UPPER-LEVEL SHORT WAVE TROUGH OVER THE WRN GREAT BASIN WILL EJECT NEWD...REACHING THE NRN/CNTRL ROCKIES BY LATE EVENING. AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR ACROSS NRN HIGH PLAINS...WITH AN ATTENDANT COLD FRONT DRAPED SWWD THROUGH THE ERN GREAT BASIN THIS AFTERNOON. IN THE EAST...AN UPPER-LEVEL LOW WILL REMAIN ANCHORED OVER NRN NEW ENGLAND. ...PORTIONS OF WY...NWRN/N-CNTRL CO... A BELT OF INTENSE MID-LEVEL SWLYS /65 TO 75 MPH AT 500 MB/ WILL OVERSPREAD THE ERN GREAT BASIN AND CNTRL ROCKIES BY NOON IN ASSOCIATION WITH THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL HELP SHIFT RICHER SUB-TROPICAL MOISTURE E OF THE CNTRL ROCKIES...WITH A CORRIDOR OF DEEP VERTICAL MIXING DEVELOPING IN ITS WAKE FROM NWRN CO ACROSS CNTRL/ERN WY. THIS MIXING SHOULD LEAD TO VERY STRONG SUSTAINED SURFACE WINDS OF 25 TO 35 MPH AT PEAK HEATING...WITH GUSTS OF 45 TO 60 MPH PROBABLE. DESPITE SUBSTANTIAL DRYING...RH VALUES SHOULD ONLY BECOME MARGINALLY LOW /AROUND 12 TO 20 PERCENT/. HOWEVER...GIVEN THE STRENGTH OF THE WINDS...LOCALIZED EXTREMELY CRITICAL CONDITIONS MAY OCCUR. ALONG THE FOOTHILLS OF THE FRONT RANGE...A PERIOD OF STRONG GUSTY WLYS APPEARS LIKELY TO DEVELOP DURING THE EVENING. LATEST NAM FORECAST SOUNDINGS INDICATE 40 TO 50 MPH WLYS IN THE LOWEST 1000-3000 FT AGL WHICH WOULD LEAD TO LOCALLY INTENSE WIND GUSTS INVOF ONGOING FIRES. THE NAM REMAINS STRONGEST OF OPERATIONAL MODEL GUIDANCE IN TEMPORAL EXTENT OF THESE WINDS PERSISTING INTO THE OVERNIGHT...WHICH WOULD RESULT IN POOR RH RECOVERY. THE LATEST GFS/ECMWF SUGGEST STRONG WLYS WILL PRIMARILY RESIDE FARTHER N IN SERN WY DURING THE OVERNIGHT...WHICH BREEDS SOME UNCERTAINTY IN THE TEMPORAL EXTENT OF CRITICAL CONDITIONS IN N-CNTRL CO. ...PORTIONS OF NERN AZ...FOUR CORNERS... ON THE SRN PERIPHERY OF THE INTENSE MID-LEVEL SWLYS OVER THE ERN GREAT BASIN TO THE CNTRL ROCKIES...SUSTAINED SURFACE WINDS SHOULD LARGELY RANGE FROM 20 TO 25 MPH THIS AFTERNOON ACROSS THE FOUR CORNERS AREA. AS SUBSTANTIAL DRYING OVERSPREADS THE REGION...RH VALUES SHOULD BECOME LOW /AROUND 10 TO 15 PERCENT/...PRIMARILY ACROSS NERN AZ. FARTHER N/E...WIDESPREAD LIGHT TO AREAS OF MODERATE RAIN ON WED SHOULD MITIGATE THE OVERALL THREAT ACROSS MOST OF ERN UT/WRN CO/NWRN NM. ...CNTRL/ERN MD...DE...NERN VA...D.C.... NWLY LOW-LEVEL FLOW WILL RESULT IN COOLER TEMPERATURES THIS AFTERNOON COMPARED TO WED /PRIMARILY IN THE MIDDLE 70S TO LOWER 80S/. THIS WILL LEAD TO MORE MARGINAL RH VALUES...IN THE UPPER 20S TO MIDDLE 30S. SUSTAINED SURFACE WINDS WILL ALSO BE SLIGHTLY WEAKER /NEAR 15 MPH/ AS THE PRESSURE GRADIENT RELAXES. HOWEVER...POTENTIAL FOR GUSTS AROUND 25 MPH SHOULD CONTRIBUTE TO AN ELEVATED FIRE WEATHER THREAT. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more
Categories: Weather
SPC Sep 9, 2010 1630 UTC Day 1 Convective Outlook
SPC 1630Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1128 AM CDT THU SEP 09 2010 VALID 091630Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY TONIGHT FOR THE NRN HIGH PLAINS... ...NRN HIGH PLAINS THIS AFTERNOON INTO EARLY TONIGHT... NO SUBSTANTIAL CHANGES TO THE PRIOR OUTLOOK AREA AND REASONING. A HIGH-AMPLITUDE TROUGH WILL MOVE EWD FROM THE NRN ROCKIES/GREAT BASIN TO THE NRN HIGH PLAINS BY EARLY FRIDAY. THE MIDLEVEL TROUGH WILL BE PRECEDED BY A LEE CYCLONE THAT WILL DEVELOP NEWD FROM SE MT TO WRN ND...WHILE S OF THE CYCLONE A LEE TROUGH WILL MOVE SLOWLY EWD THIS EVENING ACROSS THE NRN AND CENTRAL HIGH PLAINS. BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S ARE RETURNING NNWWD IN A CORRIDOR FROM NEB TOWARD WRN ND TO THE E OF THE LEE TROUGH AND S OF A WARM FRONT...AND BENEATH A PLUME OF 7-7.5 C/KM MIDLEVEL LAPSE RATES. WITH ADDITIONAL SURFACE HEATING THROUGH THE AFTERNOON... MLCAPE VALUES WILL LIKELY INCREASE TO THE 1000-2000 J/KG RANGE... WITH MINIMAL CONVECTIVE INHIBITION BY LATE AFTERNOON ALONG THE LEE TROUGH. THUNDERSTORM DEVELOPMENT IS EXPECTED BY 21-23Z NEAR THE SURFACE LOW CLOSE TO THE MT/ND BORDER...AND SWD ALONG THE LEE TROUGH NEAR THE WY/SD BORDER. DEEP-LAYER VERTICAL SHEAR AND INSTABILITY WILL BE FAVORABLE FOR SUPERCELLS AND ORGANIZED LINE SEGMENTS...WITH AN ACCOMPANYING RISK FOR LARGE HAIL AND DAMAGING WINDS. A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE THIS EVENING...PRIMARILY ACROSS NW SD/SW ND IN PROXIMITY TO THE WARM FRONT WHERE THE INITIAL STORMS WILL BE SUPERCELLULAR AND SOMEWHAT STRONGER LOW-LEVEL SHEAR WILL CORRESPOND WITH THE LOW-LEVEL MOISTURE/INSTABILITY AXIS. THE SEVERE STORM THREAT WILL BEGIN TO DIMINISH TONIGHT TOWARD THE CENTRAL DAKOTAS. ...CENTRAL/NRN AR THIS AFTERNOON... THE REMNANTS OF TROPICAL DEPRESSION HERMINE ARE MOVING ENEWD FROM NE OK/SE KS TO NW AR AND SW MO...ALONG AND N OF SURFACE WARM FRONT NEAR I-40 ACROSS AR. SURFACE-BASED STORMS CAN BE EXPECTED NEAR THE INTERSECTION OF THE WARM FRONT AND THE PRIMARY CONFLUENCE BAND WHICH EXTENDS FROM SE OK INTO NW AR...WHICH ALSO COINCIDES WITH THE BELT OF STRONGER LOW-LEVEL SLY/SWLY FLOW AND EFFECTIVE SRH IN EXCESS OF 200 M2/S2. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW ROTATING STORMS THIS AFTERNOON...AND PERHAPS A BRIEF TORNADO ...ALONG THE WARM FRONT WITH THE REMNANTS OF HERMINE...BEFORE THE SYSTEM WEAKENS AND THE BOUNDARY LAYER STABILIZES BY LATE EVENING. AT THIS TIME...THE TORNADO THREAT APPEARS TO BE REDUCED A LITTLE FROM PRIOR DAYS...SO WILL MAINTAIN 2% TORNADO PROBABILITY AREA. ..THOMPSON/ROGERS.. 09/09/2010 Read more
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1128 AM CDT THU SEP 09 2010 VALID 091630Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY TONIGHT FOR THE NRN HIGH PLAINS... ...NRN HIGH PLAINS THIS AFTERNOON INTO EARLY TONIGHT... NO SUBSTANTIAL CHANGES TO THE PRIOR OUTLOOK AREA AND REASONING. A HIGH-AMPLITUDE TROUGH WILL MOVE EWD FROM THE NRN ROCKIES/GREAT BASIN TO THE NRN HIGH PLAINS BY EARLY FRIDAY. THE MIDLEVEL TROUGH WILL BE PRECEDED BY A LEE CYCLONE THAT WILL DEVELOP NEWD FROM SE MT TO WRN ND...WHILE S OF THE CYCLONE A LEE TROUGH WILL MOVE SLOWLY EWD THIS EVENING ACROSS THE NRN AND CENTRAL HIGH PLAINS. BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S ARE RETURNING NNWWD IN A CORRIDOR FROM NEB TOWARD WRN ND TO THE E OF THE LEE TROUGH AND S OF A WARM FRONT...AND BENEATH A PLUME OF 7-7.5 C/KM MIDLEVEL LAPSE RATES. WITH ADDITIONAL SURFACE HEATING THROUGH THE AFTERNOON... MLCAPE VALUES WILL LIKELY INCREASE TO THE 1000-2000 J/KG RANGE... WITH MINIMAL CONVECTIVE INHIBITION BY LATE AFTERNOON ALONG THE LEE TROUGH. THUNDERSTORM DEVELOPMENT IS EXPECTED BY 21-23Z NEAR THE SURFACE LOW CLOSE TO THE MT/ND BORDER...AND SWD ALONG THE LEE TROUGH NEAR THE WY/SD BORDER. DEEP-LAYER VERTICAL SHEAR AND INSTABILITY WILL BE FAVORABLE FOR SUPERCELLS AND ORGANIZED LINE SEGMENTS...WITH AN ACCOMPANYING RISK FOR LARGE HAIL AND DAMAGING WINDS. A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE THIS EVENING...PRIMARILY ACROSS NW SD/SW ND IN PROXIMITY TO THE WARM FRONT WHERE THE INITIAL STORMS WILL BE SUPERCELLULAR AND SOMEWHAT STRONGER LOW-LEVEL SHEAR WILL CORRESPOND WITH THE LOW-LEVEL MOISTURE/INSTABILITY AXIS. THE SEVERE STORM THREAT WILL BEGIN TO DIMINISH TONIGHT TOWARD THE CENTRAL DAKOTAS. ...CENTRAL/NRN AR THIS AFTERNOON... THE REMNANTS OF TROPICAL DEPRESSION HERMINE ARE MOVING ENEWD FROM NE OK/SE KS TO NW AR AND SW MO...ALONG AND N OF SURFACE WARM FRONT NEAR I-40 ACROSS AR. SURFACE-BASED STORMS CAN BE EXPECTED NEAR THE INTERSECTION OF THE WARM FRONT AND THE PRIMARY CONFLUENCE BAND WHICH EXTENDS FROM SE OK INTO NW AR...WHICH ALSO COINCIDES WITH THE BELT OF STRONGER LOW-LEVEL SLY/SWLY FLOW AND EFFECTIVE SRH IN EXCESS OF 200 M2/S2. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW ROTATING STORMS THIS AFTERNOON...AND PERHAPS A BRIEF TORNADO ...ALONG THE WARM FRONT WITH THE REMNANTS OF HERMINE...BEFORE THE SYSTEM WEAKENS AND THE BOUNDARY LAYER STABILIZES BY LATE EVENING. AT THIS TIME...THE TORNADO THREAT APPEARS TO BE REDUCED A LITTLE FROM PRIOR DAYS...SO WILL MAINTAIN 2% TORNADO PROBABILITY AREA. ..THOMPSON/ROGERS.. 09/09/2010 Read more
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