MESOSCALE PRECIPITATION DISCUSSION 0229
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
703 PM EDT SAT AUG 31 2013
 
AREAS AFFECTED...EXTREME EASTERN IL...CENTRAL AND SOUTHEAST
IL...EXTREME SOUTHWEST OH...NORTHERN AND CENTRAL KY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 312255Z - 010130Z
 
SUMMARY...LINEAR BANDS OF CONVECTION WITH INTENSE RAINFALL RATES
WILL FOSTER AN INCREASED SHORT-TERM THREAT OF FLASH FLOODING.

DISCUSSION...LATEST IR SATELLITE IMAGERY SHOWS VERY COLD TOPPED
CONVECTIVE CLUSTERS ORIENTED ALONG AN AXIS FROM FAR ERN IL SEWD
DOWN INTO SERN IN...EXTREME SWRN OH AND NRN KY. SOME ADDITIONAL
CONVECTIVE ORGANIZATION IS POSSIBLE THE NEXT FEW HOURS AS A WEAK
SHORTWAVE IMPULSE OVER CNTRL IL AND AN ATTENDANT AREA OF LOW
PRESSURE ADVANCES EAST INTO THE OH VLY. THIS SHOULD TEND TO HELP
THE LOW LVL SWLY FLOW AND ASSOCD WARM ADV AIMED INTO WHAT IS NOW A
RATHER WELL DEFINED OUTFLOW BNDRY ASSOCD WITH THE ONGOING
CONVECTION. THE AIRMASS OVER THE LWR OH VLY IS QUITE UNSTABLE WITH
SBCAPE VALUES AS HIGH AS 4500 J/KG. THIS COUPLED WITH THE
APPROACHING SHORTWAVE AND LARGER SCALE WARM ADV PATTERN SHOULD
TEND TO SUSTAIN AND OR LOCALLY FOSTER MORE ORGANIZED CONVECTIVE
CLUSTERS WITH A THREAT FOR CELL MERGERS AND LOCALIZED TRAINING.

RAINFALL RATES OF UP TO 2 INCHES/HR ARE EXPECTED WITH LOCALLY
HIGHER RATES INVOF OF MERGING CLUSTERS THE NEXT FEW HOURS. GIVEN
THE SET-UP...THERE APPEARS TO BE AT LEAST AN ELEVATED SHORT-TERM
RISK OF FLASH FLOODING.

ORRISON

ATTN...WFO...RLX...JKL...ILN...LMK...IND...ILX...

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

LAT...LON   39558495 39088382 38728338 37938312 37088384 36858476
            37608579 38178619 38768713 39228783 39478822 39768825
            40198794 40218689 39868575 39558495