SPC AC 200701
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0201 AM CDT THU APR 20 2006
   
   VALID 221200Z - 231200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE DELMARVA / SRN NJ SWD
   TO THE MOUTH OF THE SAVANNAH RIVER...
   
   ...SYNOPSIS...
   
   FULL LATITUDE TROUGH /ANCHORED BY UPPER LOW OVER THE GREAT LAKES/ IS
   FORECAST TO TAKE ON A SLIGHT NEGATIVE TILT AS IT SHIFTS EWD FROM THE
   APPALACHIANS INTO THE WRN ATLANTIC.  MEANWHILE IN THE W...NEXT
   UPSTREAM LOW WILL TRANSLATE EWD INTO THE GREAT BASIN.  IN THE
   LOW-LEVELS...LEE CYCLOGENESIS IS FORECAST ALONG FRONTAL ZONE E OF
   THE BLUE RIDGE OVER CNTRL VA SATURDAY AFTERNOON WITH THIS FEATURE
   DEVELOPING NEWD INTO THE DELMARVA BY SATURDAY EVENING. IN IT/S
   WAKE...TRAILING COLD FRONT WILL PUSH EWD THROUGH THE PIEDMONT AND
   COASTAL PLAIN.
   
   ...DELMARVA / SRN NJ SWD TO THE LOWER SAVANNAH RIVER...
   
   A PRE-FRONTAL CONVECTIVE BAND OR STORM CLUSTERS ARE EXPECTED TO BE
   ONGOING SATURDAY MORNING ALONG OR JUST E OF THE APPALACHIANS WITHIN
   ZONE OF HEIGHT FALLS AHEAD OF MOBILE UPPER TROUGH.  DIABATIC HEATING
   COUPLED WITH MOIST BOUNDARY-LAYER CONDITIONS WILL CONTRIBUTE TO
   DESTABILIZATION OF DOWNSTREAM AIR MASS OVER THE PIEDMONT AND COASTAL
   PLAIN...WITH STORMS INTENSIFYING BY AFTERNOON AS THEY ENCOUNTER THIS
   STRONGER INSTABILITY.
   
   FORECAST SOUNDINGS INDICATE RELATIVELY STRONG VERTICAL SHEAR...
   ESPECIALLY ACROSS NRN PORTIONS OF SLIGHT RISK AREA OWING TO BACKED
   SURFACE WINDS AHEAD OF SURFACE LOW.  POTENTIAL WILL EXIST FOR
   SUPERCELLS AND BOWS CAPABLE OF A FEW TORNADOES...DAMAGING WINDS AND
   SEVERE HAIL.  THE SEVERE WEATHER THREAT SHOULD END SATURDAY NIGHT AS
   COLD FRONT PUSHES OFFSHORE.
   
   ...WRN / SWRN TX AND SERN NM...
   
   CO-LOCATION OF WRN EDGE OF RETURNING LOW-LEVEL MOISTURE BENEATH
   STEEP MID-LEVEL LAPSE RATES ARE EXPECTED TO CONTRIBUTE TO WEAK TO
   MODERATE AFTERNOON INSTABILITY ALONG WEAK LEE TROUGH OR DRY LINE. 
   LARGE-SCALE FORCING WILL REMAIN NEGLIGIBLE...THOUGH IT APPEARS THAT
   STRONG DIABATIC HEATING ALONG TROUGH AXIS AND/OR OROGRAPHIC FORCING
   MAY PROMOTE DIURNAL STORM DEVELOPMENT. GIVEN THE PRESENCE OF THE
   STEEP LAPSE RATES AND MODEST VERTICAL SHEAR...POTENTIAL WILL EXIST
   FOR A FEW SEVERE STORMS CAPABLE OF LARGE HAIL AND LOCALLY STRONG
   WIND GUSTS.
   
   ..MEAD.. 04/20/2006
   
   CLICK TO GET WUUS03 PTSDY3 PRODUCT

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z