Categorical Graphic
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 061254
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0754 AM CDT SAT AUG 06 2011
   
   VALID 061300Z - 071200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FROM MN
   TO NRN KS...
   
   ...MN TO NRN KS AREA THIS AFTERNOON/EVENING...
   A MIDLEVEL SHORTWAVE TROUGH...WITH SEVERAL EMBEDDED VORTICITY
   MAXIMA...WILL MOVE EWD/ESEWD FROM THE NRN PLAINS TO THE UPPER MS
   VALLEY.  A WEAK SURFACE LOW INVOF THE ND/SD/MN BORDERS WILL DEVELOP
   EWD TO NRN WI/UPPER MI BY TONIGHT...AS A DIFFUSE COLD FRONT
   PROGRESSES SEWD ACROSS THE CENTRAL PLAINS AND UPPER MS VALLEY.  IN
   ADVANCE OF THE FRONT...REGIONAL 12Z SOUNDINGS SUGGEST THE POTENTIAL
   FOR AFTERNOON MLCAPE VALUES RANGING FROM 1500 J/KG ACROSS MN TO
   2500-3000 J/KG INTO ERN NEB/KS.
   
   LOW-LEVEL SHEAR WILL NOT BE PARTICULARLY STRONG IN THE WARM
   SECTOR...BUT DEEP-LAYER SHEAR IN CONJUNCTION WITH 35-50 KT MID-UPPER
   WLY FLOW WILL BE SUFFICIENT FOR ORGANIZED SEVERE STORMS.  GIVEN THE
   EXPECTED COMBINATION OF MODERATE INSTABILITY/LAPSE RATES AND
   EFFECTIVE BULK SHEAR OF 35-45 KT...A FEW SUPERCELLS WILL BE
   POSSIBLE.  LARGE HAIL WILL BE POSSIBLE WITH THE MORE DISCRETE STORMS
   ARE EXPECTED EARLIER IN THE STORM EVOLUTION...WHILE CELL MERGERS
   SHOULD LEAD TO SOME UPSCALE GROWTH INTO ONE OR MORE CONVECTIVE
   CLUSTERS WITH AN INCREASING RISK FOR DAMAGING WINDS LATE THIS
   AFTERNOON/EVENING.
   
   ...IL TO OH TODAY...
   A CLUSTER OF STORMS IS ONGOING ACROSS CENTRAL/SRN IL...SUPPORTED BY
   LOW-LEVEL WAA WITH A WLY/WSWLY LLJ.  THIS LLJ SHOULD WEAKEN LATER
   THIS MORNING...THOUGH BELT OF MODESTLY ENHANCED WLY LOW-LEVEL SHOULD
   BE MAINTAINED ACROSS SRN IL/INDIANA THROUGH THIS AFTERNOON. 
   MEANWHILE...12Z SOUNDINGS REVEAL RATHER POOR MIDLEVEL LAPSE RATES
   OVER THE MIDWEST...AND THERE WILL BE SOME LINGERING CLOUDS FROM THE
   MORNING CONVECTION.  THE NET RESULT WILL BE RATHER MODEST
   INSTABILITY...IN AN ENVIRONMENT WITH ONLY MODEST DEEP-LAYER VERTICAL
   SHEAR.  A FEW DAMAGING GUSTS WILL CERTAINLY BE POSSIBLE THIS
   AFTERNOON WITH STORMS THAT DEVELOP ALONG A WEAK SURFACE FRONT ACROSS
   IL/INDIANA/OH...BUT THE OVERALL SEVERE STORM THREAT APPEARS TOO
   MARGINAL TO WARRANT A CATEGORICAL OUTLOOK AREA.
   
   ...NW OK TO SE KS/CENTRAL MO THIS AFTERNOON...
   A REMNANT MCV FROM OVERNIGHT CONVECTION WILL MOVE EWD FROM SE KS TO
   CENTRAL MO THIS AFTERNOON.  SURFACE HEATING IN ADVANCE OF THE MCV
   WILL CONTRIBUTE TO DESTABILIZATION AND WEAKEN THE CAP...AND MAY
   ALLOW ADDITIONAL THUNDERSTORM DEVELOPMENT.  FARTHER W...OUTFLOW WITH
   THE OVERNIGHT CONVECTION HAS MOVED SEWD INTO WRN/CENTRAL OK. 
   INTENSE SURFACE HEATING IS LIKELY ALONG AND S OF THE BOUNDARY WHICH
   WILL LIKELY RETREAT NWD THIS AFTERNOON...WITH AFTERNOON THUNDERSTORM
   DEVELOPMENT EXPECTED ALONG AND ON THE IMMEDIATE COOLER/MOISTER SIDE
   OF THE BOUNDARY.  BOTH ACROSS THIS AREA AND MO...STEEPENING
   LOW-LEVEL LAPSE RATES AND PRECIPITATION LOADING COULD SUPPORT
   ISOLATED STRONG DOWNBURSTS THIS AFTERNOON/EVENING.
   
   ..THOMPSON/ROGERS.. 08/06/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z