MESOSCALE PRECIPITATION DISCUSSION 0223
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
817 PM EDT SUN JUL 27 2014
 
AREAS AFFECTED...NE OH...PA...NJ...NRN MD...NRN DE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 280015Z - 280415Z
 
SUMMARY...FLASH FLOODING IS POSSIBLE FROM CENTRAL PA EASTWARD AS
SUPERCELLS TRAIN SLOWLY EAST AND INFLOW INCREASES TO PROMOTE NEW
DEVELOPMENT BEHIND OUTFLOWS. FARTHER WEST INTENSE DEEP LAYER
ASCENT MAY SUSTAIN A SMALL MCS CROSSING SWATHS OF RECENTLY
SATURATED GROUND.

DISCUSSION...THUNDERSTORMS WERE ALREADY TRAINING IN CENTRAL AND SE
PA. INFLOW AND MID LEVEL ASCENT WILL ONLY INCREASE THROUGH LATE
EVENING. THE SPC MESOANALYSIS DEPICTED A HEALTHY SWATH OF AT LEAST
2000 J/KG SURFACE BASED CAPE OVER VA/MD AND AHEAD OF THE ONGOING
STORMS INTO DE/NJ...SUGGESTING A LENGTHY PERIOD OF STRONG
CONVECTION WITH A MIXTURE OF SEVERE WEATHER TYPES...INCLUDING
HEAVY RAINFALL. THOUGH WIND FIELDS WERE INCREASING...SUPERCELLS
DISPLAYING DEVIANT MOTION WERE PREDICTED TO MOVE EAST AT ONLY 10
KT...AS WAS ALREADY EVIDENCED. THIS PLACES THEIR MOVEMENT ALONG
THE AXIS OF INCREASING 850 MB FLOW FROM THE SSW...WHICH WILL
CONTINUE TO YIELD SOME TRAINING. THE 12Z WRF ARW AND 21Z HRRR ARE
SIMILAR IN PREDICTING THIS SORT OF EVOLUTION...WHILE ALSO
INDICATING BACKBUILDING OF CELLS INTO CENTRAL AND PERHAPS WRN PA.
COLUMN MOISTURE WAS NOT PARTICULARLY ANOMALOUS...BUT WOULD EASILY
SUPPORT ISOLATED AMOUNTS OF 1.5 INCHES IN AN HOUR.

ERN OH/WRN PA WERE MORE STABLE NEAR THE SURFACE...BUT DEEP ASCENT
MANIFESTED BY INTENSE 12-HR HEIGHT FALLS NEARLY 90 METERS AT
700-500 MB ENDING 28/06Z...MAY SUSTAIN ELEVATED CONVECTION COMING
OFF LAKE EERIE. KCLE RADAR INDICATED WIDE SWATHS OF HEAVY RAIN AND
LITTLE HAIL. EFFICIENT RAIN COULD YIELD ANOTHER HALF INCH TO ONE
INCH OF RAIN ALONG A SWATH OF SATURATED GROUND FROM JUST EAST OF
CLEVELAND TOWARD NW PA. LOCALLY HEAVIER AMOUNTS ARE POSSIBLE WHERE
A WARM ADVECTION WING WAS FORMING AT 00Z IN THE FAR NORTHEAST
CORNER OF OH.

BURKE

ATTN...WFO...OKX...PHI...BGM...CTP...LWX...PBZ...CLE...

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

LAT...LON   40207958 39707815 39447731 39217658 39147603 39197556
            39507458 40187414 40817425 41207451 41427505 41227575
            41057704 41377845 41817997 42068079 41838178 41278172
            40207958