MESOSCALE PRECIPITATION DISCUSSION 0246
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
618 PM EDT THU MAY 31 2018

AREAS AFFECTED...SOUTHEAST KY...NORTHEAST TN...FAR WESTERN VA

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

VALID 312215Z - 010215Z

SUMMARY...TRAINING CONVECTION IN A HIGH MOISTURE ENVIRONMENT COULD
RESULT IN A FLASH FLOOD THREAT INTO THE EVENING HOURS.

DISCUSSION...REGIONAL RADARS SHOWED AN AREA OF CONVECTION DROPPING
SLOWLY SOUTHEAST ACROSS SOUTHEAST KY INTO EASTERN TN AND NEARBY
WESTERN VA. THE CONVECTION EMBEDDED DEEP MOISTURE (WITH
PRECIPITABLE WATER VALUES NEAR 2.00 INCHES...PER THE MOST RECENT
RAP ANALYSIS). THE LEADING END OF THE CONVECTION IS MOVING INTO A
MORE FAVORABLE AIRMASS...AS MLCAPE VALUES AHEAD OF THE CONVECTION
RANGE BETWEEN 1500-2000 J/KG.

THE KMRX RADAR SHOWED HOURLY RAINFALL RATES BETWEEN 1.25/1.75
INCHES OVER PORTIONS OF FAR SOUTHEAST KY AND EAST CENTRAL
TN...NEAR THE BEST INSTABILITY AND ALONG A TIGHT PRECIPITABLE
WATER GRADIENT. SOME WEAKENING OF THE CONVECTION OVER SOUTH
CENTRAL KY HAS BEEN NOTED...THOUGH THE GOES-16 CLEAN IR LOOP STILL
SHOWED BURSTS OF COLDER CLOUD TOPS.

THE CONVECTION IS EXPECTED TO MAINTAIN ITS INTENSITY THROUGH AT
LEAST 01/01Z...WHEN INSTABILITY BECOMES TO WANE AS IT BECOMES
EXHAUSTED. BEFORE THAT TIME...TRAINING IS POSSIBLE ALONG THE
LEADING EDGE OF THE CONVECTION AS IT MOVES INTO FAR SOUTHEAST
KY...EASTERN TN AND A PORTION OF WESTERN VA. THE HRRR/EXPERIMENTAL
HRRR SHOWED POCKETS OF 2.00/3.00 INCHES OF RAINFALL IN  THESE
AREAS (WITH THE HIGHEST AMOUNTS (WITH THE HIGHEST AMOUNTS OVER FAR
SOUTHEAST KY INTO EASTERN TN.

THE GENERAL EAST SOUTHEAST MOTION OF THE CONVECTION COULD MITIGATE
A LARGER FLASH FLOOD THREAT...BUT GIVEN WHAT HAS HAPPENED UPSTREAM
IN A SIMILAR AIRMASS...THERE IS A FLASH FLOOD THREAT INTO THE
EARLY EVENING.

HAYES

ATTN...WFO...JKL...LMK...MRX...OHX...RLX...RNK...

ATTN...RFC...LMRFC...MARFC...OHRFC...SERFC...

LAT...LON   37598263 37538165 37448068 36817975 36418005
            36238319 36368554 36888619 37348603 37588389