The SPC is forecasting ...severe thunderstorms expected over parts of the southeast us today....   Please read the latest public statement about this event.

   SPC AC 111233
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0733 AM CDT SUN MAY 11 2008
   
   VALID 111300Z - 121200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF COASTAL GA AND
   COASTAL SC...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE SOUTHEAST
   AND CENTRAL APPALACHIANS...
   
   ...MAJOR DERECHO/TORNADO EVENT WILL MOVE OFF GA COAST SHORTLY...
   
   EXTREMELY POWERFUL UPPER LOW OVER CENTRAL IL WILL CONTINUE TO TRACK
   EASTWARD TODAY...WHILE 90 KNOT MID LEVEL JET ROTATES THROUGH BASE OF
   LOW INTO THE OH/TN VALLEYS.  A CLUSTER OF SUPERCELL/BOW STRUCTURES
   CONTINUES TO RACE EAST-SOUTHEASTWARD AT OVER 60 KNOTS ACROSS GA
   WHERE WIDESPREAD DAMAGE HAS BEEN REPORTED.  THESE STORMS WILL MOVE
   OFFSHORE BY 14Z...LIKELY ENDING THE MOST INTENSE SEVERE WEATHER
   THREAT TODAY.  HOWEVER...CONCERN REMAINS THAT AIR MASS WILL RECOVER
   NORTHWARD INTO THE CAROLINAS AND CENTRAL APPALACHIANS BY EARLY
   AFTERNOON WITH A RISK OF RE-DEVELOPMENT OF SEVERE STORMS. 
   ALSO...SEVERE STORMS MAY STILL OCCUR OVER PARTS OF FL THIS AFTERNOON
   AND EVENING.
   
   ...GA/SC THIS MORNING...
   INTENSE DERECHO WITH EMBEDDED TORNADIC CIRCULATIONS WILL AFFECT
   PARTS OF COASTAL GA/SC THROUGH 14Z.  ONCE THIS COMPLEX MOVES
   OFFSHORE...THERE WILL REMAIN A FEW TRAILING SUPERCELLS OVER SOUTHERN
   GA THROUGH THE MORNING.  DEWPOINTS IN THE 70S...STEEP LAPSE
   RATES...AND FAVORABLE DEEP LAYER/LOW LEVEL VERTICAL SHEAR SHOWN ON
   12Z TLH SOUNDING WILL MAINTAIN A RISK OF ISOLATED TORNADOES...
   DAMAGING WINDS...AND HAIL IN THESE STORMS AS THEY SAG INTO NORTHERN
   FL.
   
   ...FL THIS AFTERNOON...
   MORNING SOUNDINGS AT JAX/TBW SHOW LARGE POTENTIAL CAPE VALUES AND
   CONSIDERABLE DEEP LAYER SHEAR.  MODEL GUIDANCE SUGGESTS THE
   POTENTIAL FOR A BROKEN LINE OF THUNDERSTORMS SAGGING INTO NORTHERN
   FL PER EARLIER DISCUSSION.  ALSO...A FEW STORMS MAY FORM AHEAD OF
   LINE ACROSS CENTRAL FL DUE TO STRONG DAYTIME HEATING AND SEA-BREEZE
   CONVERGENCE.  THESE STORMS WOULD POSE A THREAT OF HAIL/DAMAGING
   WINDS THROUGH THE EARLY EVENING IF THEY OCCUR.
   
   ...UPPER OH VALLEY AND CENTRAL APPALACHIANS...
   ARCING LINE OF THUNDERSTORMS HAS DEVELOPED AHEAD OF RAPIDLY
   DEEPENING SURFACE LOW OVER IL...EXTENDING FROM CENTRAL IND INTO
   CENTRAL KY.  THIS ACTIVITY WILL LIKELY INCREASE IN AREAL COVERAGE
   THROUGH THE MORNING AS IT DEVELOPS SOUTHWARD ALONG FRONT AND TRACKS
   INTO THE CENTRAL APPALACHIANS.  VERY STRONG LOW/MID LEVEL WIND
   FIELDS AND DRY AIR ALOFT WILL PROMOTE A RISK OF SEVERE STORMS
   CAPABLE OF LOCALLY DAMAGING WINDS THROUGH MID AFTERNOON.
   
   ...CAROLINAS/VIRGINIA...
   CONSIDERABLE UNCERTAINTY REMAINS REGARDING THE EXTENT OF
   DESTABILIZATION OVER PARTS OF THE CAROLINAS AND VIRGINIA LATER THIS
   AFTERNOON.  LARGE COMPLEX OF CONVECTION OVER GA IS SUFFICIENTLY
   ORGANIZED TO INDUCE NORTHERLY WINDS OVER ITS NORTHERN PERIPHERY. 
   THIS WILL LIKELY SUPPRESS RAPID RETURN OF RICH MOISTURE NORTHWARD
   INTO SC/NC THROUGH THE MORNING.  BY THIS AFTERNOON...RAPID RETURN
   WILL LIKELY OCCUR AHEAD OF SURFACE COLD FRONT.  PRESENT INDICATIONS
   ARE THAT VERY STRONG LOW LEVEL VERTICAL SHEAR WILL BE PRESENT ALONG
   RETREATING WARM FRONT /RUC FORECAST SOUNDINGS SUGGEST EFFECTIVE
   HELICITY VALUES OF 500-700 M2/S2/...ALONG WITH AT LEAST SOME DAYTIME
   HEATING.  OVERNIGHT MESOSCALE MODEL GUIDANCE LENDS CONFIDENCE THAT A
   FEW SEVERE/SUPERCELL STORMS MAY DEVELOP OVER PARTS OF SC/NC THIS
   AFTERNOON...POSSIBLY DEVELOPING INTO SOUTHEAST VA BY EVENING.  IF
   THIS OCCURS...TORNADOES WOULD BE POSSIBLE IN THOSE STORMS THAT ARE
   SURFACE BASED.  OTHERWISE...HAIL AND DAMAGING WINDS WOULD BE
   POSSIBLE.
   
   ..HART/JEWELL.. 05/11/2008
   
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