Jun 3, 2011 2000 UTC Day 1 Convective Outlook | |
Updated: Fri Jun 3 19:51:04 UTC 2011 | |
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic |
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Probabilistic Tornado Graphic |
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
Probabilistic Damaging Wind Graphic |
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
Probabilistic Large Hail Graphic |
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
SPC AC 031947 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0247 PM CDT FRI JUN 03 2011 VALID 032000Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS VALLEY AND GREAT LAKES REGION... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL GULF COAST STATES... SEVERAL CHANGES HAVE BEEN MADE TO THE OUTLOOK FOR 20Z. THE FIRST CHANGE IS TO CONSOLIDATE THE 30 PERCENT HAIL PROBABILITY WITH THE SIGNIFICANT HAIL HATCHED AREA AND 5 PERCENT TORNADO PROBABILITY WHERE THE MODELS ARE IN AGREEMENT CONCERNING CONVECTIVE DEVELOPMENT. THIS AREA IS ALSO COINCIDENT WITH THE STRONGEST COMBINATION OF INSTABILITY AND DEEP LAYER SHEAR. HAVE ORIENTED THE 30 PERCENT WIND DAMAGE PROBABILITY SLIGHTLY DOWNSTREAM OF THE GREATEST HAIL PROBABILITIES WHERE LINEAR MCD DEVELOPMENT WILL BE MOST LIKELY EARLY THIS EVENING. ANOTHER CHANGE TO THE OUTLOOK IS TO REMOVE NE AL...MUCH OF GA AND WRN SC FROM THE SLIGHT RISK AREA WHERE CONVECTION HAS YET TO INITIATE. HAVE CONCENTRATED THE SLIGHT RISK AREA ACROSS SRN AND CNTRL AL AND SW GA WHERE MESOANALYSIS SHOWS STRONG INSTABILITY AND SOME MODEL FORECAST INITIATE SCATTERED STORMS THIS AFTERNOON. HAVE LEFT A 5 PERCENT PROBABILITY OF WIND DAMAGE AND HAIL ACROSS THE AREA OF THE SLIGHT RISK AREA THAT WAS REMOVED. OTHER THAN THESE CHANGES...HAVE REMOVED THUNDER FROM MUCH OF THE LOWER TO MS VALLEY AND ACROSS PARTS OF THE TN VALLEY WHERE CONVECTION IS NOT FORECAST BY MOST OF THE MODEL FORECASTS. ..BROYLES.. 06/03/2011 .PREV DISCUSSION... /ISSUED 1112 AM CDT FRI JUN 03 2011/ ...SYNOPSIS... E OF THE DEEPENING COLD LOW OFF CA COAST TO LOW OVER SASKATCHEWAN/MANITOBA THERE IS A BROAD SWLY FLOW. DOWNSTREAM FULL LATITUDE RIDGE MOVES ONLY SLOWLY EWD ACROSS WRN GREAT LAKES WITH UPPER HIGH REMAINING OVER AR. N/S COLD FRONT MOVING INTO WRN MN FROM WHERE IT EXTENDS SWWD ACROSS NEB INTO SERN CO. A WEAK WAVE ALONG THE COLD FRONT IN W CENTRAL MN WITH A WARM FRONT TRAILING SEWD ACROSS SWRN WI AND WILL BE LIFTING NWD THU THE AFTERNOON ALLOWING A MOIST AND INCREASINGLY UNSTABLE AIR MASS TO SPREAD ACROSS ERN MN INTO WI. ...UPR MS VLY/WRN GRT LKS THIS AFTN THROUGH TNGT... CONSIDERABLE CLOUD COVER REMAINING FROM OVERNIGHT CONVECTION WILL CONTINUE TO THIN ACROSS ERN MN/NRN WI INTO THE AFTERNOON ALLOWING STRONG HEATING/DESTABILIZATION TO OCCUR AHEAD OF THE COLD FRONT ACROSS THE EXPANDING WARM SECTOR. THE COMBINATION OF STEEP MID LEVEL LAPSE RATES AND DEWPOINTS RISING TO AROUND 70F WILL LEAD TO MDT/STG INSTABILITY BY MID AFTERNOON WITH MLCAPES TO AOA 3000 J/KG. WITH THE PRONOUNCED EML ACROSS THE AREA...TIMING OF SURFACE INITIATION OF SEVERE THUNDERSTORMS IS A CONCERN AND APPEARS SHOULD BE DELAYED TO MID OR LATE AFTERNOON. LACK OF ANY SUBSTANTIAL UPPER FORCING WITH THE SWLY FLOW WILL LIKELY REQUIRE FULL HEATING TO OVERCOME THE CAPPING NOW IN PLACE. ONCE STORMS FORM...40-50 KT DEEP WSWLY SHEAR AND STEEP MID LVL LAPSE RATES SHOULD SUPPORT SUPERCELLS/SUSTAINED STORMS WITH LARGE HAIL...DMGG WIND...AND POSSIBLY TORNADOES. THE LATTER THREAT SHOULD BE GREATEST IN NRN WI...WHERE LOW LVL SRH SHOULD BE MAXIMIZED IN ZONE OF LOW LCLS NEAR THE WARM FRONT. BY EARLY TONIGHT...EXPECT STORMS TO MERGE INTO ONE OR MCS/S. WIND PROFILES AND THERMODYNAMIC ENVIRONMENT APPEAR FAVORABLE FOR BOWING SEGMENTS WITH AN INCREASING THREAT DMGG WIND IN WI AND POSSIBLY NRN MI. ...ERN GULF CST STATES/GA/SC THIS AFTN/EVE... MODERATE TO STRONG INSTABILITY WILL ONCE AGAIN DEVELOP WITHIN A HOT/MOIST AIR MASS OVER MUCH OF THE SOUTHEAST THIS AFTERNOON. SFC HEATING AND TERRAIN CIRCULATIONS SHOULD INITIATE SCTD AREAS OF STORMS BY MID-AFTERNOON IN WEAKLY CAPPED ENVIRONMENT. GIVEN STEEP LOW/MID-LVL LAPSE RATES AND 20+ KT MID LVL FLOW...A FEW MULTICELL CLUSTERS WITH SVR HAIL/LOCALLY DMGG WIND INTO THIS EVE. ..CNTRL PLNS LT THIS AFTN THROUGH TNGT... MODERATE INSTABILITY SHOULD DEVELOP TODAY AHEAD OF CNTRL PLNS PART OF COLD FRONT. WARM MID LVL TEMPS WILL DELAY STORM DEVELOPMENT UNTIL LATE IN THE DAY. ISOLD STORMS LATE THIS AFTN/EVE COULD YIELD DMGG WIND FROM ERN CO INTO WRN KS/SW NEB GIVEN DEEPLY MIXED BOUNDARY LAYER. STORM COVERAGE SHOULD INCREASE AFTER SUNSET AS FORCING FOR ASCENT IS AUGMENTED BY DEVELOPING JET ENTRANCE REGION ALOFT...AND BY NOCTURNAL STRENGTHENING OF SSWLY LLJ. AS STORMS SPREAD N/NE ALONG AND N OF FRONT...THEY MAY EVOLVE INTO AN MCS WITH AN ATTENDANT THREAT FOR HAIL AND PERHAPS LOCALLY DMGG WIND. HOWEVER...RELATIVELY WARM MID LVL TEMPS /AROUND MINUS 10C AT 500 MB/ AND CONGEALING OF STORMS SHOULD LIMIT OVERALL INTENSITY AND DURATION OF SVR THREAT. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z