MESOSCALE PRECIPITATION DISCUSSION 0450
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
215 PM EDT THU JUL 06 2017

AREAS AFFECTED...KY INTO FAR NRN KY AND WRN WV

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

VALID 061815Z - 070015Z

SUMMARY...REPEATING STORMS WITH PERIODS OF TRAINING WILL POSE A
FLASH FLOOD THREAT ACROSS KY INTO PORTIONS OF NRN TN AND WRN WV
INTO THE EARLY EVENING. RAINFALL RATES OF 1-2 IN/HR WILL BE COMMON
WHERE STORMS TRAIN.

DISCUSSION...17-18Z GOES VISIBLE SATELLITE IMAGERY SHOWED A
MIXTURE OF CLOUDS AND CLEARING ACROSS SRN AND ERN KY WITH
EXTENSIVE CLOUD COVER AND THUNDERSTORMS TO THE NORTH ALONG THE
OHIO RIVER. TEMPERATURES HAVE WARMED WELL INTO THE 80S WHERE
GREATER SOLAR INSOLATION HAS OCCURRED OVER KY...RAISING MLCAPE TO
1000+ J/KG...HIGHER THAN FORECAST BY THE RAP. OVER THE PAST
HOUR...CONVECTION HAS INCREASED IN COVERAGE ALONG AND SOUTH OF THE
DIFFERENTIAL HEATING BOUNDARY...AND WELL OUT AHEAD OF AN 850 MB
TROUGH/FRONT WHICH WAS LOCATED JUST NORTH OF THE OH RIVER AT 18Z.
PRECIPITABLE WATER VALUES RANGING FROM ROUGHLY 1.75 TO 2.00 INCHES
ACROSS THE OH RIVER INTO KY AND WET BULB ZERO HEIGHTS ABOVE 12 KFT
HAVE MADE FOR AN ENVIRONMENT SUPPORTIVE OF EFFICIENT RAINFALL WITH
1-2 IN/HR RATES OBSERVED EARLIER THIS MORNING NEAR THE OH RIVER.

CLOUD BEARING LAYER MEAN FLOW IS NEARLY IDENTICAL TO 850 MB FLOW
WHICH WOULD SUPPORT REPEATING STORMS AND PERIODS OF TRAINING OUT
AHEAD OF THE 850 MB BOUNDARY THIS AFTERNOON. AS STORM COVERAGE
INCREASES OVER THE NEXT 1-2 HOURS OVER KY...PERIODS OF TRAINING
AND REPEATING CELLS ARE EXPECTED TO DEVELOP AS THE ENTIRE SWATH OF
BROKEN THUNDERSTORM COVERAGE SHIFTS SLOWLY SOUTH AND EAST...AHEAD
OF THE ADVANCING UPPER LEVEL SYSTEM. A SECONDARY CONCERN IS A
REGION OF LOWER FFG THAT EXISTS ACROSS PORTIONS OF SERN KY AND TN.

ONE POTENTIAL SITUATION THAT COULD LIMIT FLASH FLOODING IS IF
STORM COVERAGE GROWS TO THE POINT THAT OUTFLOW DOMINANCE PUSHES
HEAVY RAIN IN A PROGRESSIVE MANNER TOWARD THE SOUTH. GIVEN HI-RES
MODELS HAVE NOT BEEN PERFORMING WELL ACROSS THE
REGION...CONFIDENCE IS LOWER THAN AVERAGE.

OTTO

ATTN...WFO...ILN...JKL...LMK...MRX...OHX...PAH...RLX...

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

LAT...LON   38608434 38548260 38288215 37968203 37368222
            36658345 36348481 36338606 36598770 37198772
            37718677 38108571