MESOSCALE PRECIPITATION DISCUSSION 0032
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
602 PM EDT WED APR 08 2015
 
AREAS AFFECTED...EASTERN MO...SOUTHERN IL...SOUTHERN
IN...NORTHERN/CENTRAL KY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 082200Z - 090200Z
 
SUMMARY...ADDITIONAL CLUSTERS OF HEAVY SHOWERS AND THUNDERSTORMS
ARE ANTICIPATED ALONG AND ADJACENT THE OH RIVER THROUGH
MID-EVENING. FLASH FLOODING REMAINS POSSIBLE GIVEN RECENT HEAVY
RAINS.

DISCUSSION...SHOWERS AND THUNDERSTORMS CONTINUE TO ORGANIZE AND
EVOLVE IN SEVERAL DISTINCT CLUSTERS FROM THE SOUTHERN SUBURBS OF
ST LOUIS EAST ACROSS SOUTHERN IL/SOUTHERN IN AND NORTH-CENTRAL KY.
THE ACTIVITY CONTINUES TO GENERATE AND SUSTAIN ITSELF NEAR AN
OUTFLOW BOUNDARY THAT WAS LAID DOWN EARLIER TODAY AND IS NOW BEING
REINFORCED LOCALLY BY ONGOING CONVECTION. THE BOUNDARY IS
INTERCEPTING A BROAD WARM AIR ADVECTION REGIME WITH A SIGNIFICANT
AMOUNT OF INSTABILITY TRANSPORTING NORTHEAST THROUGH THE MID MS
VALLEY AND INTO THE LOWER OH VALLEY. GOES-SOUNDER LI/S ARE AS LOW
AS -10 TO -12 OVER CENTRAL AND SOUTHWEST MO...AND LATE-DAY VIS
IMAGERY CONFIRMS THE PERSISTENCE OF CU/TCU OVER SOUTH-CENTRAL MO
WHICH IS AIDING THE ACTIVITY SOUTH OF ST LOUIS. WELL-DEFINED CLOUD
STREETS MEANWHILE ARE SEEN OVER MUCH OF WESTERN TN AND WESTERN
KY...SHOWING THE LOW LEVEL MOISTURE/INSTABILITY TRANSPORT INTO THE
OUTFLOW BOUNDARY THAT EXTENDS FARTHER EAST. ALL OF THIS
THERMODYNAMIC ENERGY WILL CONTINUE TO INTERACT WITH ONGOING
CONVECTION AND THE BOUNDARY THROUGH THE EVENING HOURS.

NO MAJOR CHANGES TO THE PREVIOUS THINKING AS FAR AS THE HIRES
GUIDANCE IS CONCERNED. THE 12Z NAM-CONEST AND RECENT RUNS OF THE
HRRR SUGGEST MULTIPLE CLUSTERS OF ORGANIZED CONVECTION WITH VERY
HEAVY RAINFALL RATES PERSISTING THROUGH 00Z AND INTO THE
MID-EVENING HOURS. CONCERNS REMAIN FOR LOCALIZED W/E TRAINING OF
SEGMENTS...ALONG WITH BACK-BUILDING CELLS AND EMBEDDED
OVERSHOOTING TOPS.

GIVEN RECENT HEAVY RAINS FOR PORTIONS OF THE THREAT AREA...THE
POTENTIAL FOR FLASH FLOODING REMAINS. 

ORRISON

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

ATTN...RFC...LMRFC...MBRFC...NCRFC...OHRFC...

LAT...LON   39208571 38888430 38468353 38048303 37358307 
            37268381 37268528 37308715 37228813 37138947 
            37369098 37769195 38099216 38379165 38518999 
            38838844 38908718