MESOSCALE DISCUSSION 0893
   NWS STORM PREDICTION CENTER NORMAN OK
   1237 PM CDT MON MAY 23 2011
   
   AREAS AFFECTED...E-CNTRL MO...CNTRL/SRN IL/IND
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 340...
   
   VALID 231737Z - 231900Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 340
   CONTINUES.
   
   FAST-MOVING BOWING LINE WILL LIKELY PRODUCE A SWATH OF DAMAGING
   WINDS EAST OF THE SAINT LOUIS METRO AREA IN PARTS OF SRN IL THROUGH
   19Z. THIS SEGMENT MAY REACH THE ERN PORTIONS OF WW 340 BY 19Z...WITH
   THE PROBABILITY OF A DOWNSTREAM WW ISSUANCE AT 80 PERCENT.
   
   AS OF 1730Z...BOWING LINE SEGMENT WITH A MEAN FORWARD PROPAGATION
   SPEED OF 50-55 KT HAD REACH THE SAINT LOUIS METRO AREA WITH A 54 KT
   GUST MEASURED AT KSTL. ENVIRONMENT WILL REMAIN SUPPORTIVE OF
   MAINTAINING THIS FEATURE EWD ACROSS SRN IL. STRONG NEARLY
   UNIDIRECTIONAL LOW/MID-LEVEL WLYS /AS SAMPLED BY WINCHESTER IL
   PROFILER/ WILL REMAIN IN PLACE...IN CONJUNCTION WITH HEATING AND
   INCREASINGLY RICH MOISTURE RETURN NOTED IN RECENT SURFACE
   OBSERVATIONS.
   
   ADDITIONAL TSTM DEVELOPMENT MAY ALSO OCCUR ALONG THE LEADING EDGE OF
   THE RICHER MOISTURE ACROSS CNTRL IL/IND WHERE CU FIELD HAS INCREASED
   PER VISIBLE SATELLITE IMAGERY. THE COMBINATION OF THE BOWING LINE
   AND/OR ADDITIONAL TSTM INITIATION WILL NECESSITATE A DOWNSTREAM
   SEVERE TSTM WATCH ISSUANCE BY 19Z.
   
   ..GRAMS.. 05/23/2011
   
   
   ATTN...WFO...LMK...IND...PAH...ILX...LSX...
   
   LAT...LON   37959032 38969029 39569035 39998958 40028817 39868741
               39138686 38838688 38538702 37898738 37668871 37959032