MESOSCALE DISCUSSION 1009
   NWS STORM PREDICTION CENTER NORMAN OK
   0539 PM CDT SAT MAY 28 2011
   
   AREAS AFFECTED...PORTIONS INDIANA...WRN OH...CENTRA/SRN IL...ERN MO.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 393...
   
   VALID 282239Z - 282345Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 393
   CONTINUES.
   
   CONTINUE WW ALONG/AHEAD OF INDIANA CONVECTION.  WW MAY BE EXTENDED
   LOCALLY AS FAR E AS RANDOLPH/DELAWARE/HENRY/RUSH
   COUNTIES...DEPENDING ON CONVECTIVE TRENDS.  ADDITIONAL WW FARTHER E
   ACROSS OH IS NOT ANTICIPATED ATTM.  AREAS FARTHER W ACROSS ERN MO
   AND SRN IL WILL BE MONITORED FOR ADDITIONAL CONVECTIVE
   DEVELOPMENT...WITH THREAT OF LARGE HAIL...THAT COULD MOVE INTO
   CURRENT WW 393 AREA BEFORE 03Z.
   
   CLUSTER OF STG-SVR TSTMS...WITH MAIN THREAT BEING LARGE
   HAIL...SHOULD CONTINUE TO MOVE EWD TO ENEWD AT 40-45 KT ACROSS
   CENTRAL INDIANA.  FCST SOUNDINGS SUGGEST INFLOW-LAYER PARCELS ALSO
   ARE CLOSE ENOUGH TO SFC-BASED THAT ISOLATED DAMAGING GUSTS ALSO MAY
   OCCUR...GIVEN SPEED OF STORM MOTIONS OVERLAID ON EVEN WEAK
   DOWNDRAFTS PENETRATING SUBCLOUD LAYER.  SVR THREAT MAY PERSIST EWD
   TO VICINITY OH/INDIANA LINE...BUT BECOMES VERY CONDITIONAL FARTHER
   E.  THREAT SHOULD DIMINISH WITH BOTH TIME AND EWD EXTENT AS COMPLEX
   ENCOUNTERS PROGRESSIVELY WEAKER INSTABILITY IN TERMS OF WEAKER LAPSE
   RATES ALOFT...STRONGER CINH ABOVE BOUNDARY LAYER...AND MORE STATIC
   STABILITY NEAR SFC.
   
   PRIMARY UNCERTAINTY ATTM IS WITH EXTENT OF POTENTIAL ELEVATED
   CONVECTIVE DEVELOPMENT ATOP CONVECTIVE COLD POOL AND N OF SFC
   FRONTAL ZONE...WHICH WAS ANALYZED AS QUASISTATIONARY NEAR
   HUF-STL-VIH LINE.  BEFORE SCHEDULED 03Z WW EXPIRATION
   TIME...STRENGTHENING SWLY LLJ WITH INCREASING MOISTURE WILL BE
   DIRECTED INTO THAT REGION...SUPPORTING POTENTIAL FOR PARCELS TO BE
   ISENTROPICALLY LIFTED TO LFC IN ENVIRONMENT OF 35-45 KT EFFECTIVE
   SHEAR MAGNITUDES.
   
   ..EDWARDS.. 05/28/2011
   
   
   ATTN...WFO...ILN...IWX...IND...LOT...ILX...LSX...
   
   LAT...LON   40218989 40718688 40818464 40248416 39498506 38758819
               38399027 38709123 39939077 40218989