MESOSCALE DISCUSSION 1708
   NWS STORM PREDICTION CENTER NORMAN OK
   1259 PM CDT TUE JUL 08 2003
   
   AREAS AFFECTED...ERN IA/NRN IL
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 679...
   
   VALID 081759Z - 081930Z
   
   THREAT FOR SEVERE HAIL AND DAMAGING WINDS REMAINS ACROSS ERN IA INTO
   NRN IL DURING THE NEXT 2-3 HOURS.
   
   17Z SURFACE ANALYSIS SHOWS THE SURFACE FRONT EXTENDING FROM SRN IA
   ENEWD TO NRN IL HAS REMAINED NEARLY STATIONARY AS OUTFLOW FROM
   CONVECTIVE COMPLEX NOW MOVING ACROSS SRN LOWER MI HAS REINFORCED THE
   SURFACE BOUNDARY.  AIR MASS ALONG AND SOUTH OF THIS BOUNDARY OR
   ACROSS SRN PORTION OF WW 679 HAS BECOME MODERATELY TO STRONGLY
   UNSTABLE.
   
   AN INCREASING POTENTIAL FOR DAMAGING WINDS EXISTS ACROSS EXTREME
   SERN IA INTO NRN IL AS A DEVELOPING BOW ECHO OVER SERN IA /CURRENT 
   EWD MOVEMENT AT 38 KT/ TRACKS ENEWD ALONG THE SURFACE FRONT/
   INSTABILITY AXIS. 
   
   REGIONAL RADARS ALSO SHOW A CLUSTERS OF STORMS OVER NWRN IL MOVING
   EWD ALONG THE SURFACE BOUNDARY WITH THIS ACTIVITY EXPECTED TO MOVE
   INTO LA SALLE COUNTY IL BY 20Z AND INTO GRUNDY...WILL AND KANKAKEE
   COUNTIES IL BY 21Z.  30 KT OF DEEP LAYER SHEAR AND MODERATE
   INSTABILITY WILL SUPPORT A HAIL AND DAMAGING WIND THREAT.
   
   ..PETERS.. 07/08/2003
   
   
   ATTN...WFO...LOT...ILX...MKX...DVN...ARX...DMX...
   
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