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 111258
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0758 AM CDT WED MAY 11 2011
   
   VALID 111300Z - 121200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER GREAT LAKES SWWD
   THROUGH THE CNTRL AND SRN PLAINS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE SERN
   STATES...
   
   ...CNTRL/SRN PLAINS...
   
   --IMPROPER HANDLING OF ONGOING STORMS FROM SWRN KS THROUGH WRN PARTS
   OF TX/OK BY MOST OF NUMERICAL GUIDANCE HAS LED TO CONSIDERABLE
   UNCERTAINTY IN SUBSEQUENT STORM EVOLUTION LATER TODAY.  AS A RESULT
   OF THIS UNCERTAINTY...THE CATEGORICAL MODERATE RISK HAS BEEN
   REMOVED.--
   
   MORNING WATER VAPOR SHOWS AN INITIAL...STRONG SHORT WAVE TROUGH
   PIVOTING AROUND UPPER LOW THROUGH THE SRN HIGH PLAINS WITH A MORE
   SUBSTANTIAL UPSTREAM PERTURBATION NEAR THE SRN AZ/NM BORDER.  THE
   FORMER FEATURE SHOULD CONTINUE TO WEAKEN WHILE PIVOTING NNEWD INTO
   THE CNTRL HIGH PLAINS TODAY WHILE THE LATTER EJECTS
   EWD...CONTRIBUTING TO AN ENHANCED ZONE OF HEIGHT FALLS/DYNAMIC
   FORCING FOR ASCENT FROM WRN KS INTO NWRN OK BY 12/00Z.  IN THE LOW
   LEVELS...ATTENDANT SURFACE CYCLONE OVER SERN CO WILL SLOWLY
   DEVELOP EWD INTO WRN KS BY AFTERNOON WITH ASSOCIATED FRONT WHICH HAS
   SETTLED SWD THROUGH CNTRL NEB LIFTING NWD/NWWD THIS AFTERNOON. 
   MEANWHILE...TRAILING DRYLINE/PACIFIC FRONT WILL PROGRESS EWD INTO
   WRN PARTS OF KS/OK AND NWRN TX LATER TODAY.
   
   STRONG-SEVERE STORMS HAVE DEVELOPED EARLY THIS MORNING ACROSS
   PORTIONS OF THE CNTRL AND SRN HIGH PLAINS IN RESPONSE TO
   ABOVE-MENTIONED...LEAD SHORT WAVE TROUGH PIVOTING NNEWD THROUGH THE
   REGION.  GIVEN THE REMOVAL OF THE CAP AND THE PRESENCE OF MUCAPE OF
   2000-3000 J/KG PER 12Z AMA SOUNDING....THERE IS REASON TO BELIEVE
   THAT THIS ACTIVITY WILL PERSIST EWD/NEWD ACROSS WRN/CNTRL PARTS OF
   KS/OK INTO THIS AFTERNOON...A SOLUTION THAT IS SUPPORTED BY THE
   11/00Z ECMWF.  THESE STORMS WILL BE CAPABLE OF SEVERE HAIL AND
   LOCALLY DAMAGING WIND GUSTS THROUGH TODAY.
   
   GIVEN THE POTENTIAL FOR WIDESPREAD CLOUDINESS AND
   CONVECTIVE-PROCESSING OF WARM SECTOR...CONSIDERABLE UNCERTAINTY
   EXISTS WITH REGARD TO THE DEGREE OF AIR MASS DESTABILIZATION THAT
   WILL OCCUR TODAY AHEAD OF THE DRYLINE.  SHOULD POCKETS OF STRONGER
   HEATING BE ABLE TO TAKE PLACE...LATEST MODEL GUIDANCE SUGGESTS THAT
   THE GREATEST THREAT FOR TORNADOES WILL EXIST NE/E OF SURFACE LOW
   FROM NWRN KS/S-CNTRL NEB INTO NWRN/N-CNTRL OK WHERE A BACKED
   LOW-LEVEL WIND FIELD WILL ENHANCE NEAR-GROUND SHEAR.  OTHERWISE...A
   CONDITIONAL THREAT FOR SUPERCELLS CAPABLE OF LARGE HAIL...A FEW
   TORNADOES AND DAMAGING WINDS WILL BE POSSIBLE ALONG DRYLINE INTO
   NWRN-N-CNTRL TX.
   
   A RISK FOR MAINLY HAIL AND DAMAGING WINDS WILL CONTINUE INTO TONIGHT
   ACROSS PORTIONS OF THE CNTRL/SRN PLAINS AS DIURNAL STORMS GROW
   UPSCALE INTO ONE OR MULTIPLE MCSS.
   
   ...CAROLINAS...
   
   EARLY MORNING VISIBLE SATELLITE IMAGERY SHOWS A WIDESPREAD CIRRUS
   CANOPY EXTENDING FROM THE CNTRL APPALACHIANS TO SERN ATLANTIC COAST.
    THIS WILL SLOW THE DESTABILIZATION PROCESS TODAY WITH EVENTUAL
   DECREASING CLOUDS FROM N-S ACROSS THE REGION.  AIR MASS ALONG AND W
   OF COMPOSITE SYNOPTIC FRONT-CONVECTIVE OUTFLOW BOUNDARY REMAINS
   MOIST WITH DEWPOINTS IN THE 60S.  THIS MOISTURE COMBINED WITH ERN
   EDGE OF STEEP MIDLEVEL LAPSE RATES WILL CONTRIBUTE TO POCKETS OF
   MODERATE INSTABILITY BY AFTERNOON WHERE MLCAPE WILL APPROACH
   1000-2000 J/KG.
   
   THE PRESENCE OF THE SURFACE BOUNDARIES...OROGRAPHIC FORCING AND THE
   SWD PROGRESSION OF WEAK IMPULSES EMBEDDED WITHIN MERIDIONAL MIDLEVEL
   FLOW REGIME ARE EXPECTED TO FOSTER SCATTERED TSTM DEVELOPMENT THIS
   AFTERNOON INTO EVENING.  GIVEN THE MODERATE INSTABILITY AND
   VERTICALLY VEERING WIND PROFILES WITH 35-45 KT OF DEEP NNWLY
   SHEAR...SETUP WILL BE SUPPORTIVE OF SUPERCELLS CAPABLE OF HAIL AND
   DAMAGING WIND GUSTS.
   
   ...UPPER MIDWEST...
   
   WATER VAPOR IMAGERY SHOWS MULTIPLE UPSTREAM VORTICITY MAXIMA WHICH
   WILL IMPACT THE REGION TODAY...ONE OVER ERN NEB/WRN IA AND THE OTHER
   OVER THE OZARK PLATEAU REGION.  THE NWD PROGRESSION OF THESE
   FEATURES WILL SUPPORT THE NWD DEVELOPMENT OF A WEAK SURFACE WAVE AND
   WARM FRONT WHICH WILL ENHANCE LOW-LEVEL CONVERGENCE.
   12Z DVN AND GRB SOUNDINGS INDICATE THAT AIR MASS IS ALREADY STRONGLY
   UNSTABLE WITH MUCAPE VALUES IN EXCESS OF 3000 J/KG.  FORCING FOR
   ASCENT ASSOCIATED WITH ABOVE-MENTIONED IMPULSES WILL FOSTER A
   CONTINUED INCREASE IN STORMS TODAY A BOUNDARY LAYER FURTHER
   WARMS/DESTABILIZING.  40-50 KT MIDLEVEL JET STREAK IS BEING OBSERVED
   ALONG ERN PERIPHERY OF VORTICITY MAXIMA WHICH WILL SERVE TO ENHANCE
   DEEP LAYER SHEAR WITH A RISK FOR SUPERCELLS CAPABLE OF LARGE
   HAIL...DAMAGING WINDS AND PERHAPS A TORNADO OR TWO.
   
   ELSEWHERE...STRONG ELEVATED INSTABILITY OBSERVED ON 12Z GRB SOUNDING
   WILL BE SUPPORTIVE OF A CONTINUED HAIL THREAT SPREADING SEWD INTO
   PORTIONS OF LOWER MI.
   
   ..MEAD/GRAMS.. 05/11/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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