SPC AC 140945
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0445 AM CDT THU AUG 14 2003
   
   VALID 161200Z - 171200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FOR THE LOWER GREAT LAKES AND
   UPPER OH VALLEY AREA....
   
   ...SYNOPSIS...
   A LARGE MID-UPPER LEVEL RIDGE WILL CONSOLIDATE OVER THE PLAINS THIS
   PERIOD...WITH DOWNSTREAM AMPLIFICATION OF A TROUGH EXPECTED OVER THE
   GREAT LAKES AND NE STATES.  ELSEWHERE...THE CLOSED/CUTOFF MID LEVEL
   LOW SHOULD REMAIN NEAR THE NW CA/ORE COASTS AS THE MAIN BELT OF
   WESTERLIES PASSES N OF THIS AREA...AND THE WEAKENING REMNANTS OF THE
   TROUGH NOW OVER TX WILL DRIFT NWWD OVER THE ROCKIES/GREAT BASIN 
   FRIDAY THROUGH SATURDAY.  LASTLY...THE EASTERLY WAVE NOW OVER S FL
   SHOULD MOVE INLAND INVOF OF S TX/NE MEXICO ON DAY 3.
   
   ...GREAT LAKES/OH VALLEY AREA...
   GRADUAL AMPLIFICATION/EXPANSION OF A MID LEVEL TROUGH IS EXPECTED
   FROM THE NEW ENGLAND/GREAT LAKES SWD TO THE UPPER OH VALLEY...
   GENERALLY AS DEPICTED BY 00/06Z OPERATIONAL MODELS.  AS THE TROUGH
   AMPLIFIES/EMBEDDED SPEED MAXIMA MOVE OVER THE REGION...AND AN
   ASSOCIATED COLD FRONT MOVES SWD...THE THREAT FOR ORGANIZED CLUSTERS
   OF THUNDERSTORMS WILL INCREASE ACROSS MI/INDIANA/OH/PA/NY DURING THE
   DAY.  BOUNDARY LAYER DEWPOINTS NOW IN THE UPPER 60S TO LOWER 70S
   ACROSS THE OH VALLEY NOW WILL BE AUGMENTED BY ANOTHER TWO DAYS OF
   EVAPOTRANSPIRATION...WHICH WILL COMBINE WITH DAYTIME HEATING TO
   SUPPORT MODERATE TO STRONG INSTABILITY BY SATURDAY AFTERNOON.  DEEP
   LAYER WINDS/VERTICAL SHEAR WILL ALSO INCREASE WITH THE APPROACH OF
   THE MID LEVEL TROUGH...RESULTING IN A FAVORABLE ENVIRONMENT FOR
   CLUSTERS OF STORMS CAPABLE OF PRODUCING WIND DAMAGE AND POSSIBLY
   LARGE HAIL.  EXPECT THIS CONVECTION AND THE ATTENDANT SEVERE STORM
   THREAT TO SPREAD SWD DURING THE AFTERNOON/EVENING...WITH GRADUAL
   WEAKENING LIKELY DURING THE OVERNIGHT HOURS.
   
   ..THOMPSON.. 08/14/2003
   
   ...NOTICE...
   FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
   LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
   GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
   HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
   INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
   
   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED FOR 1200Z