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 271247
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0747 AM CDT FRI MAY 27 2011
   
   VALID 271300Z - 281200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON FROM CENTRAL NC
   NWD TO CENTRAL PA/NY AND INTERIOR NEW ENGLAND...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON INTO
   TONIGHT FOR CENTRAL/ERN OK AND ADJACENT AREAS OF KS/MO/AR...
   
   ...CAROLINAS TO NEW ENGLAND TODAY...
   A COMPLEX MIDLEVEL TROUGH WITH MULTIPLE EMBEDDED VORTICITY CENTERS
   OVER THE APPALACHIANS WILL SLOWLY WEAKEN AND MOVE EWD/NEWD THROUGH
   TONIGHT.  A WEAK ASSOCIATED SURFACE FRONT ALONG THE APPALACHIANS
   WILL MOVE LITTLE TODAY...WHILE REMNANT OUTFLOWS FROM OVERNIGHT
   CONVECTION GRADUALLY LOSE DEFINITION NEAR AND W OF THE I-95
   CORRIDOR.  MEANWHILE...A FAVORABLY MOIST ENVIRONMENT REMAINS ACROSS
   THE ATLANTIC COASTAL PLAIN WHERE BOUNDARY LAYER DEWPOINTS ARE IN THE
   MID-UPPER 60S THIS MORNING.
   
   SURFACE HEATING WITH THINNING CLOUDS WILL RESULT IN DESTABILIZATION
   ALONG AND E OF THE SLOW-MOVING FRONT...SUPPORTING THE DEVELOPMENT OF
   SCATTERED THUNDERSTORM CLUSTERS BY MID AFTERNOON FROM INTERIOR NEW
   ENGLAND TO CENTRAL NY/PA.  AFTERNOON MLCAPE VALUES ARE EXPECTED TO
   REACH 1000-2000 J/KG IN THIS ZONE...WHERE A BELT OF 35-50 KT
   MIDLEVEL FLOW WILL PERSIST.  THESE FACTORS WILL FAVOR ORGANIZED
   MULTICELL CLUSTERS AND SOME EMBEDDED SUPERCELL STRUCTURES...WITH AN
   ATTENDANT RISK FOR DAMAGING WINDS AND LARGE HAIL.  THE SEVERE THREAT
   IS EXPECTED TO PEAK LATE THIS AFTERNOON...BUT THEN DIMINISH QUICKLY
   THIS EVENING WITH THE ONSET OF BOUNDARY LAYER COOLING AND CONTINUED
   WEAKENING OF THE SYNOPTIC WAVE.  
   
   FARTHER S INTO THE CAROLINAS...THE THUNDERSTORM CLUSTER OVER THE
   SAVANNAH RIVER WILL LIKELY PERSIST AS A WEAK VORT MAX ROTATES NEWD
   AND THE DOWNSTREAM BOUNDARY LAYER DESTABILIZES.  THOUGH LOW-MIDLEVEL
   FLOW HAS WEAKENED THIS MORNING PER REGIONAL VWP/S...FLOW WILL REMAIN
   SUFFICIENT FOR ORGANIZED MULTICELL CLUSTERS THROUGH MID AFTERNOON
   FROM NC NWD INTO VA.  THE SLIGHT RISK HAS BEEN EXPANDED SWD ACROSS
   VA/NC TO ACCOUNT FOR THE RISK OF DAMAGING WINDS BY MIDDAY INTO THE
   AFTERNOON AS THE MORNING CONVECTION EXPANDS NEWD AND INTENSIFIES
   WITH DAYTIME HEATING.
   
   ...SRN PLAINS THIS AFTERNOON INTO TONIGHT...
   LEE CYCLOGENESIS WILL CONTINUE ACROSS THE SRN HIGH PLAINS IN
   ASSOCIATION WITH EMBEDDED SPEED MAXIMA EJECTING EWD OVER KS/OK ON
   THE SRN FRINGE OF THE STRONG MID-UPPER JET OVER THE CENTRAL ROCKIES.
    THIS WILL MAINTAIN A 25-40 KT SLY LLJ ACROSS CENTRAL/E TX AND
   OK...AND ALLOW A WARM FRONT ACROSS CENTRAL/SE TX TO MOVE NWD INTO OK
   THIS AFTERNOON/EVENING.  MOISTURE ADVECTION AND DAYTIME
   HEATING/MIXING WILL PROMOTE DOWNWARD MIXING OF MOISTURE ALONG AND S
   OF THE WARM FRONT...WHICH COMBINED WITH AFTERNOON TEMPERATURES OF
   85-90 F WILL SUPPORT MLCAPE VALUES OF 2000-3000 J/KG IN CENTRAL/ERN
   OK.  A PRONOUNCED LOW-LEVEL WAA REGIME WILL BE PRESENT OVER
   OK...BENEATH 50 KT WLY/WNWLY FLOW ALOFT...RESULTING IN FAVORABLE
   VERTICAL SHEAR FOR RIGHT-MOVING SUPERCELLS.  
   
   CONVECTIVE INITIATION IS MORE PROBABLE THIS AFTERNOON INTO TONIGHT
   INVOF SE KS.  THIS AREA WILL BE N OF THE WARMEST PORTION OF THE
   EML...AND WILL BE ALONG THE PATH OF A LOW-AMPLITUDE SHORTWAVE TROUGH
   NOW OVER SW KS.  FARTHER S IN OK...FORECAST SOUNDINGS SUGGEST A MORE
   CONDITIONAL SEVERE THREAT AS CONVECTIVE INHIBITION WEAKENS WITH
   DAYTIME HEATING/MIXING.  IF ISOLATED STORMS FORM LATE THIS
   AFTERNOON/EVENING ACROSS CENTRAL/NE OK...THE ENVIRONMENT WILL FAVOR
   SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL AND ISOLATED DAMAGING
   GUSTS.  WILL MAINTAIN ONLY LOW TORNADO PROBABILITIES GIVEN THE
   UNCERTAINTY REGARDING STORM FORMATION...AND RELATIVELY LARGE
   TEMPERATURE-DEWPOINT SPREADS IN THE BOUNDARY LAYER.
   
   ..THOMPSON/GARNER.. 05/27/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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