MESOSCALE PRECIPITATION DISCUSSION 0541
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
644 AM EDT SUN JUL 23 2017

AREAS AFFECTED...SOUTHWEST IN & WESTERN KY

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 231043Z - 231443Z

SUMMARY...CELL MERGERS AND CELL TRAINING SHOULD CONTINUE FLASH
FLOOD CONCERNS FOR 3-4 MORE HOURS.  HOURLY RAIN RATES UP TO 2.5"
WITH LOCAL AMOUNTS UP TO 4" ARE POSSIBLE.

DISCUSSION...A FORWARD PROPAGATING ARC OF CONVECTION IS MOVING
QUICKLY THROUGH SOUTHERNMOST IL INTO SOUTHERN IN AND WESTERN KY
WHERE TRAINING CONVECTION IS ONGOING.  PRECIPITABLE WATER VALUES
OF 2-2.25" LIE IN THIS REGION PER GPS DATA.  INFLOW AT 850 HPA IS
WEST-NORTHWEST AT 30 KTS IS IMPORTING MU CAPES OF 1000-2000 J/KG
FROM IL INTO THE REGION.  EFFECTIVE BULK SHEAR OF 25-35 KTS ALONG
WITH UNIDIRECTIONAL FLOW WITH HEIGHT HAS AIDED THE DEVELOPMENT OF
TRAINING CONVECTIVE BANDS.

THE 06Z NAM CONEST AND RANDOM OLDER RUNS OF THE HRRR/EXPERIMENTAL
HRRR HAVE HAD A CLUE IN THIS REGION.  WHILE CLOUD TOPS IN THE
TRAINING ACTIVITY HAVE BEEN WARMING SOMEWHAT, THE EXPECTATION IS
THAT THE FORWARD PROPAGATING CONVECTIVE ARC FROM IL WILL MERGE
WITH THE TRAINING CONVECTION ENHANCING RAIN RATES/COOLING CLOUD
TOPS BRIEFLY AND SHORTENING THE TRAINING BANDS WITH TIME.  HOURLY
RAIN RATES UP TO 2.5" WITH LOCAL AMOUNTS UP TO 4" ARE POSSIBLE
UNTIL THE MERGER PROCESS IS COMPLETE AND THE BAND FORWARD
PROPAGATES AWAY AND WEAKENS.

ROTH

ATTN...WFO...ILX...IND...LMK...PAH...

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

LAT...LON   38768729 38768663 38568601 37738610 37498740
            37818824 38268829 38668803