MESOSCALE PRECIPITATION DISCUSSION 0154
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1026 AM EDT WED JUL 10 2013
 
AREAS AFFECTED...CENTRAL IL...FAR WESTERN IN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 101420Z - 101800Z
 
SUMMARY...SLOW-MOVING AND ORGANIZING COLD-TOPPED CONVECTION
PRODUCING VERY INTENSE RAINFALL RATES. EXPECTING SOME POTENTIAL
FOR SHORT-TERM FLASH FLOODING.

DISCUSSION...LATEST IR SAT IMAGERY SHOWS RAPIDLY COOLING
CONVECTIVE TOPS OVER CNTRL IL IN ASSOC WITH AN APPROACHING COLD
FRONT AND UPPER LVL SHORTWAVE TROUGH AXIS OVER THE MIDWEST. 12Z
RAOB DATA OVER THE MIDWEST COUPLED WITH GOES-SOUNDER DATA
INDICATES A VERY UNSTABLE AIRMASS THIS MORNING OVER ESPECIALLY
CNTRL IL AND DOWNWIND INTO MUCH OF IN...WITH LI/S LOCALLY TO NEAR
-10 AND MUCAPE VALES AOA 3000 J/KG. WV IMAGERY INDICATES RATHER
DIV FLOW ALOFT SUGGESTING LARGER SCALE ASCENT. PROPAGATION VECTORS
ARE RATHER WEAK OFF TO THE EAST ATTM...SUGGESTING A CONTINUATION
OF SLOW-MOVING ACTIVITY AND A GRADUAL EVOLUTION OF CONVECTION
THROUGH CNTRL IL AND INTO WRN IN. THE LATEST SAT/RADAR TRENDS
SUGGEST A LIKELIHOOD OF CELL MERGERS...AND THERE MAY WELL BE AN
ORGANIZED MCS THAT EVOLVES OUT OF THE ABUNDANCE OF MULTI-CELL
CONVECTION. SLOW-MOVEMENT COUPLED WITH CELL MERGERS AND A PWAT
ENVIRONMENT NEAR 2 INCHES WILL SUPPORT RAINFALL RATES OF 2 TO 2.5
INCHES/HR. THUS EXPECTING SOME SHORT-TERM FLASH FLOOD
CONCERNS...WITH SEVERAL INCHES POSSIBLE IN ONLY A 2 TO 3 HOUR
PERIOD.

ORRISON

ATTN...WFO...IWX...IND...LOT...ILX...LSX...

ATTN...RFC...NCRFC...OHRFC...

LAT...LON   39118773 38928857 38888953 39249047 39769049 40109016
            40518876 40598779 40558630 39868594 39368669 39118773