MESOSCALE DISCUSSION 1919
   NWS STORM PREDICTION CENTER NORMAN OK
   0253 PM CDT WED AUG 19 2009
   
   AREAS AFFECTED...WRN OK AND FAR SRN KS
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 191953Z - 192115Z
   
   CORRECTED FOR SECOND PARAGRAPH WIND DESCRIPTION
   
   PORTIONS OF WRN OK AND FAR SRN KS ARE BEING MONITORED FOR
   THUNDERSTORM INITIATION AND A CORRESPONDING INCREASE IN SEVERE
   WEATHER POTENTIAL. A WW MAY BE NECESSARY.
   
   WV IMAGERY SHOWS A LARGE SCALE TROUGH CENTERED OVER THE CENTRAL
   CONUS...WITH ONE UPPER IMPULSE DIVING SEWD INTO THE CENTRAL HIGH
   PLAINS...WHILE A LEAD WAVE PIVOTS E TOWARD THE MID-UPPER MS VALLEY
   REGION. THE CENTRAL HIGH PLAINS DISTURBANCE IS DRIVING A COLD FRONT
   THROUGH WRN NEB...WHILE A SUBTLE PV STREAMER TRAILS THE MS VALLEY
   IMPULSE SW INTO THE SRN HIGH PLAINS. THIS PV STREAMER IS ASSOCIATED
   WITH A CIRRUS BAND THAT IS LOCATED FROM WRN TX INTO SW AND CENTRAL
   OK...WHERE IT INTERSECTS A SURFACE OUTFLOW BOUNDARY LEFT OVER FROM
   EARLY CONVECTION LIFTING NEWD THROUGH SERN KS/NERN OK. LOW 70S
   DEWPOINTS RESIDE ALONG THE OUTFLOW BOUNDARY INTO WRN/NWRN OK...WHILE
   STRONG SURFACE HEATING /TEMPERATURES IN THE 90S TO AROUND 100 DEG F/
   IS BUILDING NNE INTO SWRN OK. THE ZONE RESIDING BETWEEN THE STRONGER
   HEATING AND COOLER BUT MOIST BOUNDARY LAYER AIRMASS IS EXPECTED TO
   EXPERIENCE STRONGEST DESTABILIZATION AND LARGEST THETA-E
   VALUES...CONTRIBUTING TO MLCAPE VALUES AOA 2000 J/KG AS A PLUME OF
   STEEP MID LEVEL LAPSE RATES CONTINUES TO SPREAD E INTO THE REGION.
   
   FORCING FOR CONVECTIVE INITIATION IS EXPECTED TO REMAIN SOMEWHAT
   WEAK/SUBTLE DURING THE AFTERNOON...BUT THE PRESENCE OF THE MID/UPPER
   LEVEL PV FEATURE INTERSECTING THE SURFACE OUTFLOW
   BOUNDARY...COMBINED WITH CONTINUED BOUNDARY LAYER
   DESTABILIZATION...MAY LEAD TO STORM DEVELOPMENT BY MID TO LATE
   AFTERNOON. AREA VWP DATA INDICATES THAT SELY SURFACE WINDS ALONG AND
   TO THE COOL SIDE OF THE BOUNDARY INCREASE TO 30-40 KT FROM THE SW IN
   THE LOWEST 2 KM/S...AND THEN INCREASE FURTHER TO 40-50 KT WSWLY FLOW
   IN THE MID LEVELS. THESE WIND PROFILES WILL FAVOR POSSIBLE SUPERCELL
   DEVELOPMENT...POSING A THREAT OF LARGE HAIL GIVEN THE STEEPENING
   LAPSE RATES AND FAVORABLY STRONG /AOA 40 KT/ EFFECTIVE BULK SHEAR.
   LOW LEVEL SHEAR PROFILES ARE ALSO MAXIMIZED ALONG AND TO THE COOL
   SIDE OF THE OUTFLOW BOUNDARY /CHARACTERIZED BY 0-1 KM SRH VALUES AOA
   100 M2 S-2/...ALONG WITH FAVORABLY LOW LCL HEIGHTS...WHICH SUGGESTS
   THAT A TORNADO THREAT WILL ALSO EXIST.
   
   ..GARNER.. 08/19/2009
   
   
   ATTN...WFO...ICT...OUN...DDC...
   
   LAT...LON   34789878 35139956 36399973 37149928 37099763 36119711
               34939746 34789878