SPC AC 210725
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0125 AM CST FRI NOV 21 2008
   
   VALID 231200Z - 241200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   A DEEP UPPER LOW IS FORECAST TO DIG FROM MANITOBA/SASKATCHEWAN SEWD
   INTO THE WRN GREAT LAKES BY LATE SUNDAY. AN INTENSE SHORTWAVE TROUGH
   WILL EXTEND SWD FROM THIS LOW AND MOVE EWD FROM THE PLAINS STATES
   INTO MS/WRN TN/OH VALLEYS. A WEAK FRONT WILL ACCOMPANY THE TROUGH
   AND SHOULD STRETCH ROUGHLY FROM THE CENTRAL GREAT LAKES SSWWD
   THROUGH THE MIDDLE MS VALLEY AND INTO ERN/SRN TX BY DAYBREAK MONDAY.
   
   ...AR/WRN TN NEWD INTO THE WRN OH VALLEY...
   AHEAD OF THE APPROACHING UPPER TROUGH/COLD FRONT...SLY WINDS ARE
   EXPECTED TO ADVECT LOWER TO MID 50 DEWPOINTS INTO THE MID MS VALLEY
   SUNDAY NIGHT. THIS INCREASED MOISTURE COMBINED WITH FRONTAL
   CONVERGENCE AND INCREASING UVV/S SHOULD BE SUFFICIENT FOR CONVECTION
   TO DEVELOP NEAR THE FRONT LATE IN THE PERIOD. DESPITE DEEP LAYER
   SHEAR AT 50KT...WEAK INSTABILITY AND POOR MID LEVEL LAPSE RATES
   INDICATES ANY SEVERE THREAT WOULD BE VERY LIMITED.
   
   ..IMY.. 11/21/2008