MESOSCALE DISCUSSION 0871
   NWS STORM PREDICTION CENTER NORMAN OK
   0524 PM CDT WED MAY 23 2007
   
   AREAS AFFECTED...WRN/NRN WI...SERN MN...NRN AND CENTRAL IA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 291...292...
   
   VALID 232224Z - 240030Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   291...292...CONTINUES.
   
   A NEARLY SOLID LINE OF STG TO SVR TSTMS WILL CONTINUE TO MOVE EWD
   AROUND 20 KTS ACROSS WW/S 291/292 /FROM WRN WI SWWD INTO SERN MN AND
   MUCH OF CENTRAL IA/ OVER THE NEXT FEW HOURS. SOME OF THE SVR STORM
   MOTIONS OVER WRN WI HAVE BEEN MUCH FASTER THAN FURTHER SOUTH ALONG
   THE LINE /40-45 KTS/ AND MAY MOVE OUT OF WW 291 BEFORE WEAKENING.
   THUS THE AREA OF NCENTRAL/WCENTRAL WI MAY NEED TO BE MONITORED FOR
   THE POSSIBILITY OF LOCAL WFO EXTENSION OF WW 291 EWD A FEW COUNTIES.
   ALTHOUGH AN ISOLATED TORNADO IS POSSIBLE...THE PRIMARY SVR MODE
   SHOULD BE LINEAR WITH DMGG WINDS/LARGE HAIL THE MAIN SVR THREATS.
   
   LATEST RADAR IMAGERY SHOWS A NEARLY SOLID LINE OF STG-SVR TSTMS FROM
   NWRN WI SWWD INTO CENTRAL IA. AIRMASS AHEAD OF THIS ACTIVITY WILL
   REMAIN MODERATELY UNSTABLE FROM WRN WI INTO NERN IA WITH MUCAPES
   AROUND 1500 J/KG. ALONG WITH MODERATE VERTICAL SHEAR...THERE REMAINS
   SUFFICIENT SUPPORT FOR A CONTINUED SVR THREAT FOR THE NEXT SEVERAL
   HOURS. THE GREATEST SVR WIND THREAT APPEARS TO BE OVER WRN
   WI...CLOSER TO THE STRONGER MID LEVEL WINDS WHERE SEVERAL BOW
   SEGMENTS HAVE BEEN MOVING ENEWD FROM 40-45 KTS. MODERATE LOW LEVEL
   SHEAR /100 M2/S2 OF 0-1 KM SRH/ OVER WRN WI AHEAD OF THIS LINE MAY
   BE SUFFICIENT FOR A BRIEF BOW ECHO TORNADO WITHIN EMBEDDED LINE
   SEGMENTS OR AN ISOLATED TORNADO WITH ANY DISCRETE CELLS OVER FAR
   NCENTRAL WI. STEEP MID LEVEL LAPSE RATES WILL CONTINUE TO SUPPORT A
   THREAT FOR SVR HAIL...ESPECIALLY OVER WW 292 /CENTRAL IA/.
   
   ..CROSBIE.. 05/23/2007
   
   
   ATTN...WFO...MQT...DLH...ARX...MPX...DMX...OAX...
   
   46899125 45449256 43709349 42799411 41959504 41149513
   40639474 40619419 40949389 41019361 41289337 41809336
   42329305 42599266 43049224 43449191 43569174 43849170
   43939136 44279148 44619138 44639093 45419089 45429071
   45949073 46008997 46438990