MESOSCALE DISCUSSION 1228
   NWS STORM PREDICTION CENTER NORMAN OK
   0238 AM CDT FRI JUN 19 2009
   
   AREAS AFFECTED...FAR SOUTHERN WI/NORTHEAST IL INTO LOWER MI/NORTHERN
   INDIANA/NORTHWEST OH
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 473...
   
   VALID 190738Z - 190915Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 473
   CONTINUES.
   
   SEVERE TSTM WATCH 473 CONTINUES UNTIL 12Z. DAMAGING WINDS AND VERY
   HEAVY RAINFALL WILL REMAIN A CONCERN THROUGH THE OVERNIGHT ACROSS
   FAR SOUTHERN WI AND NORTHEAST IL/CHICAGO METRO AREA INTO LOWER
   MI/NORTHERN INDIANA. MONITORING FOR AN ADDITIONAL WATCH ACROSS
   PORTIONS OF LOWER MI/NORTHEAST INDIANA/NORTHWEST OH.
   
   EXTENSIVE GENERAL WEST-EAST ORIENTED/QUASI-LINEAR MCS CONTINUES
   ACROSS THE SOUTHERN LAKE MICHIGAN VICINITY. THE EASTERN HALF OF THE
   CONVECTIVE LINE WILL CONTINUE TO POSE THE PRIMARY DAMAGING WIND
   THREAT FROM THE CHICAGO AREA INTO SOUTHWEST LOWER MI/NORTHERN
   INDIANA THROUGH THE OVERNIGHT. MEAN FLOW IS LARGELY PARALLEL TO THE
   CONVECTIVE LINE...BUT AN INCREASINGLY EXTENSIVE COLD POOL/FORWARD
   PROPAGATION WILL SUPPORT SOME SOUTH-SOUTHEASTWARD BOWING WITH
   ATTENDANT DAMAGING WIND THREAT. MORE RECENT DEVELOPMENT HAS ALSO
   BEEN NOTED ACROSS NORTHEAST INDIANA IN VICINITY OF A
   NORTHWEST-SOUTHEAST ORIENTED WARM FRONT. AMPLE LOW LEVEL SRH/DEEP
   LAYER FLOW PER RECENT NORTH WEBSTER WSR-88D VWP SUGGESTS UPDRAFT
   ROTATION WILL BE POSSIBLE WITH THESE MCS-LEADING QUASI-DISCRETE
   STORMS...WITH ATTENDANT SEVERE HAIL/PERHAPS EVEN A TORNADO
   POTENTIAL.
   
   FARTHER WEST...A RATHER MOIST/UNSTABLE FEED...VIA A 35-40 KT
   WESTERLY LOW LEVEL JET ACROSS IA...AND BOUNDARY PARALLEL MEAN FLOW
   WILL SUPPORT TRAINING ECHOES/INTENSE RAINFALL RATES ACROSS FAR
   SOUTHERN WI INTO ADJACENT NORTHERN IL/CHICAGOLAND THIS MORNING.
   
   ..GUYER.. 06/19/2009
   
   
   ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...MKX...
   DVN...
   
   LAT...LON   42699040 43119038 43038897 42538747 42798613 42738482
               40678329 39898518 41098806 41908978 42699040