Midwest Chasing

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 498
   NWS STORM PREDICTION CENTER NORMAN OK
   225 PM CDT MON JUL 9 2007

   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 

          NORTHEAST ILLINOIS
          LAKE MICHIGAN

   EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 225 PM UNTIL 800
   PM CDT.

   HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40
   STATUTE MILES NORTH AND SOUTH OF A LINE FROM 55 MILES NORTHEAST
   OF MEIGS FIELD ILLINOIS TO 30 MILES SOUTH OF ROCKFORD ILLINOIS.
   FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
   OUTLINE UPDATE (WOUS64 KWNS WOU8).

   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.

   OTHER WATCH INFORMATION...CONTINUE...WW 494...WW 495...WW
   496...WW 497...

   DISCUSSION...THUNDERSTORMS ALONG A COLD FRONT AND OUTFLOW BOUNDARY
   WILL DEVELOP SEWD FROM WI INTO NE IL THIS AFTERNOON.  THE STORMS
   WILL BE FED BY A VERY MOIST AND UNSTABLE AIR MASS...WHICH WILL
   SUPPORT A THREAT FOR AT LEAST MARGINALLY SEVERE HAIL AND DAMAGING
   DOWNBURSTS...DESPITE RATHER WEAK VERTICAL SHEAR.