MESOSCALE DISCUSSION 1833
   NWS STORM PREDICTION CENTER NORMAN OK
   1257 PM CDT TUE AUG 02 2011
   
   AREAS AFFECTED...CNTRL/ERN IA...FAR SERN MN...SRN/CNTRL
   WI...CNTRL/NRN IL
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 021757Z - 021930Z
   
   PORTIONS OF CNTRL/ERN IA...FAR SERN MN...SRN/CNTRL WI AND CNTRL/NRN
   IL ARE BEING MONITORED FOR SURFACE BASED THUNDERSTORM INITIATION.
   THIS WILL LIKELY TAKE PLACE BY MID AFTERNOON. ONE OR MORE WW/S WILL
   THEN BE NEEDED ACROSS THE AREA.
   
   AT 17Z...SURFACE ANALYSIS INDICATED A MOBILE AREA OF LOW PRESSURE
   WAS CENTERED 30 WNW OF LSE IN FAR SERN MN. A WARM FRONT EXTENDED EWD
   FROM THE LOW ACROSS SRN WI...WHILE A COLD FRONT TRAILED SWWD INTO
   CNTRL IA. STRONG HEATING IS OCCURRING ALONG AND S OF THE WARM
   FRONT...WITH TEMPERATURES RISING INTO THE UPR 80S TO LOW 90S.
   HOWEVER...VISIBLE SATELLITE PRESENTATION OF TOWERING CUMULUS FORMING
   ALONG THE COLD FRONT IN NERN IA SUGGESTS THE ATMOSPHERE REMAINS
   CAPPED THUS FAR. LATEST SHORT TERM MODEL GUIDANCE INDICATES THIS
   WILL CHANGE BY MID AFTERNOON...AS CONTINUED SURFACE HEATING AND
   FRONTAL CONVERGENCE/ASCENT AIDS IN THUNDERSTORM INITIATION INVOF THE
   WARM AND COLD FRONTAL BOUNDARIES. 
   
   LINE SEGMENTS AND STORM CLUSTERS WILL BE POSSIBLE ALONG THE COLD
   FRONT...AND WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL/DAMAGING
   WINDS GIVEN MLCAPE VALUES AOA 3000 J/KG...30+ KT MIDLEVEL WLYS
   OVERSPREADING THE FRONT...AND A HOT BOUNDARY LAYER/STEEP LOW-LEVEL
   LAPSE RATE ENVIRONMENT. THIS ACTIVITY WILL THEN MOVE EWD INTO
   PORTIONS OF CNTRL/NRN IL...WHERE IT MAY GROW UPSCALE INTO A QLCS.
   FARTHER N OVER PORTIONS OF SRN/CNTRL WI...AREA VWP/S AND RUC
   FORECAST SOUNDINGS INDICATE THE POTENTIAL FOR LOWER CLOUD BASES AND
   STRONGER LOW AND DEEP LAYER VERTICAL WIND SHEAR...FAVORABLE FOR
   ROTATING UPDRAFTS. THOUGH DAMAGING WINDS/LARGE HAIL WILL BE THE
   PRIMARY SVR WEATHER THREATS...TORNADOES WILL ALSO BE POSSIBLE WITH
   ANY STORMS THAT INTERACT WITH THE SURFACE WARM FRONT.
   
   ..GARNER.. 08/02/2011
   
   
   ATTN...WFO...GRB...LOT...ILX...MKX...DVN...ARX...DMX...
   
   LAT...LON   40599137 41019351 42779342 44209053 44498776 43408682
               41848763 40948936 40599137