MESOSCALE PRECIPITATION DISCUSSION 0184
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
934 PM EDT TUE MAY 22 2018

AREAS AFFECTED...FAR SOUTHEAST OH...CENTRAL/NORTHERN WV...FAR
WESTERN MD

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

VALID 230130Z - 230430Z

SUMMARY...A BAND OF HEAVY SHOWERS AND THUNDERSTORMS WILL ADVANCE
SOUTHEAST OVER THE NEXT COUPLE OF HOURS. GIVEN THE VERY WET
ANTECEDENT CONDITIONS...SOME FLASH FLOODING WILL BE POSSIBLE.

DISCUSSION...A COLD FRONT DROPPING SOUTHEAST ACROSS THE OH VALLEY
CONTINUES TO FOSTER A BROKEN LINE OF HEAVY SHOWERS AND
THUNDERSTORMS. CLOUD TOPS OVER THE LAST COUPLE OF HOURS HAVE BEEN
TENDING TO COOL A BIT MORE AS THE CONVECTION CONTINUES TO WORK
THROUGH A MODERATELY UNSTABLE AIRMASS POOLED UP AHEAD OF THE
FRONT. SOME WEAK RIGHT-ENTRANCE REGION JET DYNAMICS ARE IN PLACE
AS WELL WHICH IS PROVIDING SOME LARGER SCALE ASCENT.

THE CONVECTION AS IT SETTLES SOUTHEAST DOWN ACROSS THE CENTRAL
APPALACHIANS WILL BE CAPABLE OF PRODUCING RAINFALL RATES OF 1.5 TO
2 INCHES/HR WITHIN THE STRONGER CORES...AND WITH THE ANTECEDENT
CONDITIONS SO WET...THERE WILL BE SOME SHORT-TERM CONCERNS FOR
ENHANCED RUNOFF AND FLASH FLOODING. THIS IS SUPPORTED BY VERY LOW
FFG VALUES ACROSS THE REGION.

THE ACTIVITY SHOULD WEAKEN TOWARD MIDNIGHT AS THE AVAILABLE
INSTABILITY BECOMES INCREASINGLY EXHAUSTED...AND AT THAT TIME THE
FLASH FLOOD THREAT SHOULD DIMINISH. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...CTP...LWX...PBZ...RLX...

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

LAT...LON   39737930 39317919 38797982 38638076 38588158
            38628214 38988255 39308239 39568172 39678117
            39728030