MESOSCALE PRECIPITATION DISCUSSION 0282
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
708 PM EDT SUN MAY 28 2017

AREAS AFFECTED...NORTHEAST OH...WESTERN PA...EXTREME NORTHWEST
MD...NORTHEAST WV

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 282306Z - 290306Z

SUMMARY...SHOWERS AND THUNDERSTORMS EXTENDING FROM NORTHEAST OH
ACROSS WESTERN PA INTO THE NORTHEAST CORNER OF WV AND EXTREME
NORTHWEST MD WILL CONTINUE A FLASH FLOOD THREAT OVER THE AREA FOR
THE NEXT SEVERAL HOURS.

DISCUSSION...SHOWERS AND THUNDERSTORMS ARE OCCURRING OVER AN AREA
OF LOW FLASH FLOOD GUIDANCE FROM NORTHEAST OH ACROSS WESTERN PA TO
THE NORTHEAST CORNER OF WV AND EXTREME NORTHWEST MD. THE SHOWERS
ARE OCCURRING IN A VERY MOIST ENVIRONMENT WITH ONLY MODEST
INSTABILITY. PRECIPITABLE WATER VALUES ARE 1.4-1.8" AND MUCAPE IS
GENERALLY 500-1000 J/KG. THE STORMS ARE EFFICIENT RAIN PRODUCERS
THOUGH...WITH LOCAL HOURLY RAIN RATES OF 1-2".

THE MAIN LINE OF STORMS HAS BEEN DECENTLY PROGRESSIVE ACROSS
PA...BUT STORMS HAVE BEEN REDEVELOPING IN THE WAKE OF THAT LINE
OVER WESTERN PA AND ACROSS NORTHEAST OH FOR A TRAINING EFFECT.
HIRES MODELS INDICATE THE ACTIVITY WILL CONTINUE THROUGH
EVENING...WITH MOST OF THE MODELS SHOWING LOCAL ACCUMULATIONS OF
MORE THAN 2". THE 3-HOUR FLASH FLOOD GUIDANCE VALUES IN THE THREAT
AREA ARE IN THE RANGE 0.75-2.0"...SO ADDITIONAL FLASH FLOODING IS
LIKELY THIS EVENING.

MCDONNAL

ATTN...WFO...CLE...CTP...LWX...PBZ...

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

LAT...LON   41937867 41637722 40117795 39347841 39147892
            39537972 40618043 40938123 41018238 41538256
            41688202 41878111