MESOSCALE PRECIPITATION DISCUSSION 0283...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
533 AM EDT SUN AUG 17 2014
 
AREAS AFFECTED...PORTIONS OF MID-MISSISSIPPI VALLEY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 170919Z - 171319Z
 
SUMMARY...BROAD 30-45 KNOT 850 HPA INFLOW HAS CAUSED A RECENT
EXPANSION OF THUNDERSTORM ACTIVITY ACROSS SOUTHERN IL, WHICH
SHOULD SHIFT SOUTHWARD INTO WESTERN KY WITH TIME.  FLASH FLOODING
IS POSSIBLE.

DISCUSSION...RECENT REDEVELOPMENT OF CONVECTION ACROSS SOUTHERN IL
NEAR A STATIONARY FRONT APPEARS TIED TO A RECENT INCREASE OF 850
HPA INFLOW FROM 30-45 KNOTS PER AREA VAD WIND PROFILES.  THIS IS
CAUSING SOME CELL TRAINING ACROSS SOUTHERN IL, WHICH HAS RECEIVED
3-5" OF RAIN OVER THE PAST FEW HOURS PER RADAR ESTIMATES, NEAR
THEIR FLASH FLOOD GUIDANCE.  THIS STRENGTHENED INFLOW HAS BEEN
ABLE TO TAP FAIRLY DISTANT 500+ J/KG CAPE ACROSS SOUTHEAST MO.

THE EXPECTATION, NOW THAT THE INFLOW HAS INCREASED, IS FOR CELL
TRAINING ACROSS SOUTHERN IL AND WESTERN KY ACROSS THE NEXT SEVERAL
HOURS.  NONE OF THE MESOSCALE QPF HAS BEEN CLOSE TO CORRECT
CONCERNING THE MAGNITUDE OF THE PRECIPITATION THUS FAR, OTHER THAN
THE 12Z RUN OF EXREF MEMBER NUMBER 7 AND A RANDOM RUN OF THE HRRR
FROM SEVERAL HOURS AGO.  HOURLY RAIN RATES OF UP TO 2.5" AN HOUR
ARE SUPPORTED FROM THE 2.25" PRECIPITABLE WATER VALUES, WHICH
COULD LEAD TO 3-5" OF RAINFALL WHERE CELLS TRAIN FOR 1-2 HOURS.  

ROTH

ATTN...WFO...OHX...IND...PAH...ILX...MEG...LSX...

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

LAT...LON   37208717 36278819 36018952 38008907 38788989 38938906
            38588783 38078729 37208717