MESOSCALE DISCUSSION 0522
   NWS STORM PREDICTION CENTER NORMAN OK
   0814 PM CDT SAT APR 18 2009
   
   AREAS AFFECTED...N CNTRL TX THROUGH CNTRL AND ERN OK...SERN KS AND
   SW MO
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 168...170...
   
   VALID 190114Z - 190245Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   168...170...CONTINUES.
   
   THREAT FOR ISOLATED STRONG TO DAMAGING WIND GUSTS AND LARGE HAIL
   WILL PERSIST FOR ANOTHER COUPLE HOURS...BUT OVERALL TREND SHOULD BE
   FOR THREAT TO DIMINISH AFTER 03Z. 
   
   STORMS CONTINUE DEVELOPING ALONG AND AHEAD OF EWD ADVANCING FRONT
   THROUGH CNTRL OK. OTHER STORMS ARE DEVELOPING ALONG AXIS OF WEAK
   WARM ADVECTION FROM ERN OK THROUGH SW MO AND SE KS. AN INCREASE IN
   INTENSITY HAS RECENTLY BEEN OBSERVED WITH STORMS ACROSS CNTRL OK
   ALONG OUTFLOW/COLD FRONT MERGER. THE 00Z RAOB DATA FROM NORMAN AND
   SPRINGFIELD INDICATE THE ATMOSPHERE IS ONLY MARGINALLY UNSTABLE.
   SURFACE TEMPERATURES ARE IN THE MID 50S...BUT THE BOUNDARY LAYER IS
   NOT WELL MIXED AND DRIES OUT ABOVE THE SURFACE LAYER. WITH THE ONSET
   OF NOCTURNAL COOLING...THE SEVERE THREAT SHOULD BECOME INCREASINGLY
   MARGINAL TOWARD MID EVENING OR AFTER 03Z. GREATEST COVERAGE OF
   STORMS WILL LIKELY REMAIN ACROSS OK INTO KS AND MO WHERE STRONGER
   FORCING FOR ASCENT ATTENDING THE EJECTING SHORTWAVE TROUGH WILL
   EXIST. COVERAGE WILL LIKELY REMAIN MORE ISOLATED FARTHER SOUTH
   ACROSS NORTH CNTRL TX WHERE THE FORT WORTH RAOB DATA AND WV IMAGERY
   INDICATE VERY DRY AIR ABOVE 700 MB...LIKELY DUE TO PRESENCE OF LARGE
   SCALE SUBSIDENCE.
   
   ..DIAL.. 04/19/2009
   
   
   ATTN...WFO...SGF...TSA...ICT...FWD...OUN...
   
   LAT...LON   37449347 34899450 34529569 32599691 32709782 35029742
               36869704 37679539 37449347