MESOSCALE PRECIPITATION DISCUSSION 0363
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
315 PM EDT TUE JUN 26 2018

AREAS AFFECTED...CNTRL AND ERN TN...ERN KY...EXTREME SRN OH...SWRN
VA

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

VALID 261915Z - 262300Z

SUMMARY...A CONVECTIVE COMPLEX, WITH TRAINING ALONG THE SOUTHERN
FLANK, AND AREAS OF TRAINING CELLS OUT AHEAD OF IT WILL PRODUCE
AREAS OF HEAVY RAIN THROUGH 23Z. FLASH FLOODING IS POSSIBLE.

DISCUSSION...A LONG-LIVED CONVECTIVE COMPLEX/SQUALL LINE CONTINUES
TO PRESS EASTWARD ACROSS KY THIS AFTERNOON, PRODUCING AREAS OF
HEAVY RAINFALL. LATEST RADAR ESTIMATES WITHIN THE CONVECTIVE LINE
SHOW RAINFALL RATES OF 1-2 IN/HR AT TIMES. ALONG THE SOUTHERN
EDGE, SOME CELL TRAINING WAS NOTED ALONG THE OUTFLOW BOUNDARY,
WHICH WAS ORIENTED WITH A SIGNIFICANT PERPENDICULAR COMPONENT IN
THE LOW-LEVEL FLOW. AHEAD OF THE LINE, A BROAD REGION OF LOW-LEVEL
CONVERGENCE ALONG WITH A SURFACE FRONTAL BOUNDARY ARE SUPPORTING
THE DEVELOPMENT OF ADDITIONAL CONVECTIVE CELLS, SOME OF WHICH ARE
SLOW-MOVING AND/OR TRAINING GIVEN RELATIVELY WEAK LOW-LEVEL FLOW.
LATEST GOES-16 SATELLITE IMAGERY SUGGEST THAT THE INTENSITY OF THE
CONVECTIVE COMPLEX MAY HAVE PEAKED, WITH A GRADUAL WARMING OF
CLOUD TOPS NOTED OVER THE PAST HOUR. INSTABILITY REMAINS ABUNDANT
TO THE SOUTH/EAST OF THE COMPLEX (MLCAPES OF 1500-2500 J/KG),
HOWEVER, WHICH COMBINED WITH CONTINUED UPPER-LEVEL DIFFLUENT FLOW,
SHOULD KEEP THE WEAKENING PROCESS RELATIVELY SLOW. ADDITIONALLY,
PW VALUES ARE NEAR 2 INCHES, SUPPORTING A HIGH DEGREE OF
PRECIPITATION EFFICIENCY.

AS A RESULT, A CONTINUED EASTWARD PROGRESSION OF THE COMPLEX IS
EXPECTED THROUGH THE NEXT SEVERAL HOURS, WITH A PERSISTENT THREAT
FOR RATES OF 1-2 IN/HR IN SOME AREAS. THE HRRR AND HRRR-EXP BOTH
SHOW THIS GENERAL SCENARIO, WITH THE COMPLEX SLOWLY WEAKENING AS
IT REACHES THE APPALACHIANS OVER THE NEXT FEW HOURS, AND BOTH
INDICATING THE POTENTIAL FOR LOCALIZED ADDITIONAL RAINFALL AMOUNTS
THROUGH 23Z EXCEEDING 2 INCHES. ADDITIONAL AREAS OF HEAVY RAIN MAY
CONTINUE OUT AHEAD OF THE MAIN LINE IN SLOW-MOVING OR REDEVELOPING
CELLS. FINALLY, CONTINUED AREAS OF TRAINING MAY OCCUR ON THE
OUTFLOW ALONG THE SOUTHERN FLANK OF THE CONVECTIVE COMPLEX GIVEN
THE 20 KT SOUTHWESTERLY LOW-LEVEL FLOW.

RYAN

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

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

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            36178257 35788357 35578452 35648600 36098662
            36458654 36658593 36958504 37658462 38538449
            38958405