MESOSCALE DISCUSSION 0567
   NWS STORM PREDICTION CENTER NORMAN OK
   0532 PM CDT SAT APR 25 2009
   
   AREAS AFFECTED...NERN MO...ERN IA...NRN IL...SRN WI...EXTREME NWRN
   IND
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 252232Z - 252345Z
   
   CORRECTED FOR TYPO
   
   THUNDERSTORM COVERAGE WILL CONTINUE TO INCREASE ACROSS NERN MO...ERN
   IA...NRN IL...SRN WI...AND EXTREME NWRN IND THROUGH THE EVENING. A
   WATCH DOES NOT APPEAR NECESSARY AT THIS TIME...BUT CONVECTIVE TRENDS
   WILL CONTINUE TO BE MONITORED.
   
   AT 21Z...A SLOW MOVING COLD FRONT WAS OBSERVED EXTENDING NEWD FROM
   THE KANSAS CITY METRO AREA TOWARD NRN IL AND EWD INTO SRN MI. A
   COOL/STABLE BOUNDARY LAYER AIRMASS EXISTS NORTH OF THE FRONT...WHILE
   TEMPERATURES HAVE WARMED INTO THE 70S AND 80S TO ITS SOUTH...AND
   SURFACE DEWPOINTS RESIDE IN THE LOW 60S...CONTRIBUTING TOWARD MLCAPE
   VALUES AROUND 1000-1500 J/KG. RRQ OF 160 KT ULJ RESIDES OVER THE
   REGION...AND SEVERAL WEAK UPR LVL IMPULSES ARE EMANATING OUT OF
   CNTRL/SRN PLAINS. THESE FEATURES ARE PROVIDING FAVORABLE LARGE SCALE
   ASCENT FOR DESTABILIZATION...WHILE MESOSCALE ASCENT ALONG AND N OF
   FRONT IS FORECAST TO INCREASE DURING THE NIGHT AS SWLY LLJ
   STRENGTHENS TO 30-50 KT. STORMS WILL CONTINUE TO INCREASE IN
   COVERAGE AS A RESULT...INCLUDING LOCATIONS N OF THE SURFACE FRONT AS
   MUCAPE INCREASES TO 1000 J/KG. 
   
   FORECAST SOUNDINGS AND VWP DATA INDICATE SHEAR VALUES WILL FAVOR
   MAINLY MULTICELL STORM TYPES DURING THE NEXT FEW HRS...WITH A
   GRADUAL INCREASE IN LOW LVL SHEAR LIKELY AS THE LLJ STRENGTHENS
   DURING THE NIGHT. STORMS FORMING IN THIS ENVIRONMENT MAY BE CAPABLE
   OF PRODUCING MARGINALLY SVR HAIL AND PERHAPS AN ISOLATED DAMAGING
   WIND GUST...BUT THE THREAT DOES NOT APPEAR TO WARRANT A WATCH AT
   THIS TIME. HOWEVER...CONVECTIVE TRENDS WILL BE MONITORED FOR AN
   INCREASE IN STORM ORGANIZATION.
   
   ..GARNER.. 04/25/2009
   
   
   ATTN...WFO...LOT...ILX...MKX...LSX...DVN...ARX...
   
   LAT...LON   42638737 42128711 41318751 39479042 39709179 41089205
               42379179 43099040 43198878 43058821 42638737