SPC MESOSCALE DISCUSSION 1189 FOR SRN MN/CNTRL WI 
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL...
   
   VALID 211817Z - 212000Z
   
   CONVECTIVE TRENDS ARE BEING MONITORED FOR INCREASING SEVERE THREAT
   AND POSSIBILITY OF WW.
   
   REGIONAL VAD WIND DATA/MODEL PROGS INDICATE 40 TO 50 KT MID-LEVEL
   JET STREAK ASSOCIATED WITH SHORT WAVE TROUGH MIGRATING AROUND
   NORTHERN PERIPHERY OF SUBTROPICAL RIDGE.  BELT OF STRONGER FLOW
   CURRENTLY EXTENDS IN AN EAST-WEST BAND FROM SOUTHEAST SOUTH DAKOTA
   INTO CENTRAL WISCONSIN...WITH SHORT WAVE TROUGH MIGRATING EASTWARD
   ACROSS CENTRAL MINNESOTA.  MID-LEVEL FORCING FOR UPWARD VERTICAL
   MOTION AHEAD OF THIS FEATURE...AND ASSOCIATED UPSTREAM/DOWNSTREAM
   WARM ADVECTION REGIMES HAVE SUPPORTED EXTENSIVE ONGOING CONVECTIVE
   SYSTEM OVER THE UPPER MISSISSIPPI VALLEY.
   
   ACTIVITY AT THE PRESENT TIME APPEARS TO BE ROOTED ABOVE SHALLOW
   STABLE SURFACE LAYER...NORTH OF WEAK SURFACE FRONT WHICH EXTENDS
   FROM NORTHERN IOWA INTO THE SOUTHERN GREAT LAKES REGION.  HOWEVER
   ...AIR MASS NORTH OF BOUNDARY IS RATHER MOIST ACROSS SOUTHEAST
   MINNESOTA AND CENTRAL WISCONSIN...WITH SURFACE DEW POINTS IN THE
   LOWER/MID 60S.  WITH SEVERAL HOURS OF AFTERNOON SURFACE HEATING
   SOUTH OF CLOUD SHIELD ACROSS MUCH OF CENTRAL WISCONSIN...BOUNDARY
   LAYER WILL DESTABILIZE...AND STORMS SHOULD BECOME INCREASINGLY
   SURFACE-BASED AS THEY PROGRESS EASTWARD...WITH POTENTIAL FOR GUSTS
   NEAR/ABOVE SEVERE LIMITS.  PEAK WIND GUSTS IN EXCESS OF 30 KTS HAVE
   ALREADY BEEN SAMPLED BY SURFACE OBSERVATIONS ACROSS SOUTHERN
   MINNESOTA.
   
   ..KERR.. 06/21/02