SPC AC 220515
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1115 PM CST SAT NOV 21 2009
   
   VALID 221200Z - 231200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   
   DEEP-LAYER CYCLONE CURRENTLY OVER THE LOWER MS VALLEY IS FORECAST TO
   WEAKEN THROUGH THE DAY ONE PERIOD AS IT EVOLVES INTO AN OPEN WAVE
   WHILE TRANSLATING NEWD TOWARD THE MID ATLANTIC COAST.  ATTENDANT
   SURFACE CYCLONE WILL CONCURRENTLY WEAKEN OVER THE FAR NERN GULF OF
   MEXICO BEFORE REFORMING TONIGHT OFF THE SERN ATLANTIC COAST. 
   PERSISTENT SURFACE RIDGING E OF THE APPALACHIANS SHOULD SUPPORT
   INTENSIFICATION OF W-E ORIENTED BAROCLINIC ZONE TODAY ACROSS NRN FL
   WITH ANY THREAT OF SEVERE WEATHER REMAINING CONFINED TO ALONG AND S
   OF THIS BOUNDARY.
   
   ...NRN FL/SRN GA...
   
   GRADUALLY WEAKENING SWLY LLJ WILL BE MAINTAINED AHEAD OF EJECTING
   SHORT WAVE TROUGH...SUPPORTING AN INCREASE IN DEWPOINTS THROUGH THE
   60S S OF FRONTAL ZONE.  DESPITE THE INCREASING BOUNDARY LAYER
   MOISTURE...POOR LAPSE RATES /MOST NOTABLY IN THE 700-500 MB LAYER/
   WILL EFFECTIVELY LIMIT THE DEGREE OF AIR MASS DESTABILIZATION WITH
   MLCAPE REMAINING GENERALLY BELOW 1000 J/KG.
   
   TSTMS CURRENTLY IN PROGRESS OVER THE NERN GULF OF MEXICO ARE
   EXPECTED TO SPREAD NEWD ACROSS THE REGION TODAY WITHIN SRN FRINGE OF
   STRONGER DYNAMIC FORCING FOR ASCENT ASSOCIATED WITH DE-AMPLIFYING
   MIDLEVEL WAVE.  A BELT OF 45-50 KT SWLY MIDLEVEL FLOW WILL ACCOMPANY
   VORTICITY MAXIMUM NEWD...EFFECTIVELY CONTRIBUTING TO AROUND 40 KT OF
   DEEP-LAYER SHEAR ACROSS NRN EXTENSION OF SYSTEM WARM SECTOR.  THIS
   INCREASE IN VERTICAL SHEAR MAY BE SUFFICIENT TO SUPPORT EPISODIC
   SUPERCELL AND/OR BOWING STRUCTURES EMBEDDED WITHIN LARGER-SCALE
   CONVECTIVE SYSTEM.  WHILE AN ISOLATED STRONG WIND GUST OR BRIEF
   TORNADO ARE POSSIBLE...THE WEAK LAPSE RATES...MARGINAL CONVECTIVE
   INSTABILITY AND OVERALL WEAKENING OF SYNOPTIC SYSTEM WITH TIME ARE
   EXPECTED TO PRECLUDE A MORE ROBUST SEVERE WEATHER THREAT.
   
   ..MEAD/GRAMS.. 11/22/2009
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z