MESOSCALE DISCUSSION 0617
   NWS STORM PREDICTION CENTER NORMAN OK
   0352 PM CDT SUN APR 29 2007
   
   AREAS AFFECTED...NERN IA...SRN WI...FAR NRN IL
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 292052Z - 292215Z
   
   ISOLATED TO WIDELY SCATTERED HIGH-BASED TSTMS SHOULD CONTINUE TO
   DEVELOP ALONG PRE-FRONTAL SURFACE TROUGH OVER THE NEXT FEW HOURS.
   ALTHOUGH DEEP-LAYER SHEAR PROFILES ARE SUFFICIENT FOR ROTATING
   UPDRAFTS...RELATIVELY WEAK FORCING AND LIMITED INSTABILITY WILL
   LIKELY MITIGATE A MORE WIDESPREAD SEVERE WEATHER THREAT. THUS...A WW
   APPEARS UNLIKELY ATTM...BUT TRENDS WILL CONTINUE TO BE MONITORED.
   
   ISOLATED TSTMS HAVE RECENTLY DEVELOPED ALONG AN E-W ORIENTED SURFACE
   TROUGH FROM AROUND 40 S RST TO 40 S LSE. TEMPERATURES WITHIN THIS
   AXIS HAVE REACHED THE MIDDLE TO UPPER 80S WHILE ASOS REPORTED DEW
   POINTS HAVE MIXED TO THE MIDDLE TO UPPER 40S. GIVEN THE NEARLY 40
   DEGREE DEW POINT DEPRESSIONS...STEEP LOW-LEVEL LAPSE RATES MAY
   CONTRIBUTE TO A DRY MICROBURST THREAT AS THE TSTMS MATURE SEWD.
   STRONG 0-6 KM SHEAR OF 40 TO 45 KTS /AS SAMPLED BY THE LA CROSSE VAD
   PROFILER/...WILL BE ADEQUATE FOR LARGE HAIL DEVELOPMENT AS WELL.
   HOWEVER...THE STRONGEST FORCING WILL REMAIN WELL NORTHEAST OF THE
   AREA IN ASSOCIATION WITH A MID-LEVEL SHORT WAVE TROUGH MOVING SEWD
   NE OF LK SUPERIOR. IN ADDITION...CONVECTIVE COVERAGE SHOULD LARGELY
   BE DRIVEN BY RELATIVELY WEAK CONVERGENCE ALONG THE SURFACE TROUGH
   AND/OR COLD FRONT. TO THE S OF THE SURFACE TROUGH...LATEST OBJECTIVE
   ANALYSIS INDICATES A CAPPING INVERSION REMAINS WITH LIMITED
   INSTABILITY /MLCAPES AOB 500 J/KG/.
   
   ..GRAMS.. 04/29/2007
   
   
   ATTN...WFO...LOT...MKX...DVN...ARX...DMX...
   
   42088805 42179040 42429189 42679303 42939350 43429395
   43469337 43489169 43669032 43708828 42918790