MESOSCALE DISCUSSION 0855
   NWS STORM PREDICTION CENTER NORMAN OK
   0149 PM CDT SUN MAY 22 2011
   
   AREAS AFFECTED...ERN WI...NRN IL
   
   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 
   
   VALID 221849Z - 221945Z
   
   CONDITIONS WILL CONTINUE TO RAPIDLY EVOLVE THIS AFTERNOON AND A
   TORNADO WATCH WILL LIKELY BE NEEDED FROM ERN WI INTO NRN IL.
   
   SURFACE MAP SHOWS RELATIVELY DRY AIR IN PLACE OVER ERN WI/NRN IL
   WITH DEWPOINTS ONLY IN THE 50S F. HOWEVER...MID 60S TO NEAR 70S F
   BOUNDARY LAYER DEWPOINTS ARE LURKING UPSTREAM OVER SERN IA AND CNTRL
   IL...AND WILL MOVE INTO THE AREA BY EVENING. ALSO AT THAT
   TIME...WIND PROFILES WILL HAVE BECOME MORE FAVORABLE FOR SUPERCELLS
   WITH A THREAT OF TORNADOES.  THE 18Z DVN SOUNDING SHOWS VERY STEEP
   LAPSE RATES ALOFT WITH MINIMAL CAPPING...ALONG WITH AMPLE DEEP LAYER
   WIND FIELDS FOR ORGANIZED SEVERE. 
   
   ACTIVITY HAS FORMED ALONG THE GRAVITY WAVE OVER CNTRL IL...AND THEY
   MAY BECOME BETTER ORGANIZED WITH TIME. FARTHER N... A LEAD BAND OF
   CONVECTION WILL TRAVERSE WI WITH PERHAPS A MARGINAL HAIL THREAT.
   HOWEVER...THE GREATEST SEVERE THREAT WILL EVOLVE OUT OF THE DRYLINE
   STORMS OVER E CNTRL IA AND NRN MO...WITH TORNADOES AND VERY LARGE
   HAIL AS THEY CROSS THE MS INTO WI AND IL.
   
   ..JEWELL.. 05/22/2011
   
   
   ATTN...WFO...MQT...GRB...LOT...ILX...MKX...DVN...ARX...
   
   LAT...LON   41068933 42688945 44458993 45259071 45518888 45128755
               44268741 41148764 41068933