MESOSCALE DISCUSSION 2041
   NWS STORM PREDICTION CENTER NORMAN OK
   0125 AM CDT MON SEP 28 2009
   
   AREAS AFFECTED...ERN IND/OH
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 746...747...
   
   VALID 280625Z - 280730Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   746...747...CONTINUES.
   
   A FAST-MOVING BROKEN LINE OF STORMS EXTENDING FROM ERN LOWER MI SWWD
   TO ERN IND/FAR WRN OH PER REGIONAL RADAR IMAGERY WILL PROGRESS EWD
   OVERNIGHT...AND SHOULD EXIT WATCHES 746 AND 747 BY 07Z.  THIS
   ACTIVITY WAS GENERALLY LOCATED JUST AHEAD OF A COLD FRONT ATTENDANT
   TO A VIGOROUS SHORTWAVE TROUGH AMPLIFYING ESEWD INTO THE GREAT
   LAKES/OH VALLEY REGION.  RADAR DATA INDICATED THE STRONGEST STORM
   WAS MOVING EWD THROUGH WEST CENTRAL OH /SHELBY AND AUGLAIZE
   COUNTIES/ WHERE HAIL 1 INCH OR LESS IN DIAMETER HAS BEEN REPORTED.
   
   STRONG FORCING FOR ASCENT WITHIN THE EXIT REGION OF A 100 KT WLY MID
   LEVEL JET ROUNDING BASE OF THE SHORTWAVE TROUGH WILL CONTINUE TO
   SPREAD EWD INTO THE OH VALLEY.  THIS COMBINED WITH LOW LEVEL WAA
   AHEAD OF THE COLD FRONT WILL MAINTAIN THE TSTMS ALONG AND AHEAD OF
   THE COLD FRONT.  ALTHOUGH THESE STORMS ARE MOVING EWD AT 50 KT...
   SURFACE OBSERVATIONS IN THE VICINITY OF THIS ACTIVITY SINCE 05Z HAVE
   INDICATED WIND GUSTS TO AROUND 30 KT.  THUS...ACTIVITY IS LIKELY
   ELEVATED.  THE STRONGEST STORM OVER WEST CENTRAL OH IS LIKELY BEING
   FED FROM THE A VEERING LLJ WHICH CURRENTLY IS PROVIDING A FEED OF
   MARGINAL TO MODERATE INSTABILITY INTO SWRN-WRN OH.  THIS COMBINED
   WITH STEEP MID LEVEL LAPSE RATES MAY PROVE SUFFICIENT FOR A FEW
   ADDITIONAL HAIL EVENTS.  HOWEVER...AS THE UPPER TROUGH PROGRESSES
   EWD OVERNIGHT...STRONGER FORCING FOR ASCENT AND TSTM ACTIVITY ARE
   EXPECTED TO MOVE EAST OF THE BETTER MOISTURE/INSTABILITY FEED. 
   THUS...A DOWNSTREAM WATCH IS NOT EXPECTED TO ISSUED.
   
   ..PETERS.. 09/28/2009
   
   
   ATTN...WFO...CLE...ILN...DTX...LMK...IWX...IND...
   
   LAT...LON   39028569 40388457 41738405 41688224 40288237 38648339
               38948553 39028569