SPC MESOSCALE DISCUSSION 1740 FOR SERN IA / NERN MO / CENTRAL IL...
   CONCERNING...HEAVY RAINFALL...
   
   VALID 190833Z - 191200Z
   
   THUNDERSTORMS ARE FORECAST TO CONTINUE FOR THE NEXT SEVERAL HOURS
   IN A W-E LINE OR LINES FROM THE IA / MO BORDER EWD INTO CENTRAL IL. 
   RAINFALL RATES OF 1 TO 2 INCHES PER HOUR CAN BE EXPECTED FOR
   SEVERAL HOURS WITH LOCALLY HIGHER AMOUNTS.
   
   LATEST SURFACE ANALYSIS SHOWS WARM FRONT LYING FROM N CENTRAL MO
   NORTH OF IRK ENEWD ACROSS EXTREME SERN IA TOWARD THE CHICAGO AREA. 
   AIRMASS SOUTH OF THIS BOUNDARY REMAINS VERY MOIST...WITH SURFACE
   DEWPOINTS IN THE LOW 70S AND EVENING RAOBS INDICATING MOIST AIRMASS
   THROUGH 600 TO 700 MB AND PW VALUES IN EXCESS OF 1.5 INCHES.
   
   STRONG LOW-LEVEL JET HAS NOW VEERED TO WSWLY ACROSS THE REGION...
   RESULTING IN ROUGHLY UNIDIRECTIONAL DEEP-LAYER WIND PROFILES --
   NEARLY PARALLEL TO THE SURFACE BOUNDARY.  AS A RESULT...STORMS WILL
   LIKELY REMAIN ALIGNED ROUGHLY PARALLEL TO THE SURFACE BOUNDARY /
   MEAN WIND -- AND THUS TRAINING / BACKBUILDING STORMS ARE FORECAST
   WHICH WILL LIKELY RESULT IN VERY HEAVY RAINFALL OVER THE NEXT FEW
   HOURS.  
   
   ..GOSS.. 08/19/02