MESOSCALE PRECIPITATION DISCUSSION 0255
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1222 AM EDT SUN JUN 21 2015
 
AREAS AFFECTED...DELAWARE...NEW JERSEY...EASTERN PA...SOUTHERN NY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 210421Z - 211021Z
 
SUMMARY...HEAVY RAIN REMAINS A THREAT FOR THE NEXT SEVERAL HOURS
WITH POST TROPICAL BILL AND ACTIVE SQUALL LINE.

DISCUSSION...THE COMBINATION OF POST TROPICAL BILL AND A VAGUE
FRONTAL ZONE WILL CONTINUE TO RESULT IN LOCALLY HEAVY RAIN FROM
DELAWARE/NEW JERSEY AND EASTERN PA NORTHEASTWARD. DEEP TROPICAL
MOISTURE INVOF OF BILL AND THE FRONTAL ZONE REMAIN WELL ABOVE 2
INCHES AND THIS MOISTURE PLUME SHOULD SPREAD OFF TO THE NORTH AND
EAST. IT APPEARS THERE WILL BE TWO ZONE OF HEAVY RAIN WITHIN
THREAT ZONE... ONE IN THE UNSTABLE AIR MASS ACROSS DE/SOUTHERN NJ
WITH THE PROPAGATING SQUALL LINE WITH INDIVIDUAL LINE SEGMENTS AND
ANOTHER AREA ACROSS NORTHEASTERN PA/NORTHERN NJ INTO SOUTHERN NY
STATE INCLUDING THE NYC METRO AREA WITH ALMOST AN INTENSE
ISENTROPIC/WARM ADVECTION PATTERN. WHAT'S LEFT OF BILL WILL TRACK
OFF TO THE EAST-NORTHEAST TO SOUTHEASTERN PA/SOUTHERN NJ... WHILE
ONSHORE FLOW DIRECTED INTO THE SOUTHERN NEW ENGLAND COASTLINE WITH
THE QUASI-STATIONARY BOUNDARY IN PLACE COULD YIELD ANOTHER ZONE OF
HEAVY RAINS NEAR THE TAIL END OF THIS MPD.

MUSHER

ATTN...WFO...AKQ...ALY...BGM...BOX...CTP...LWX...OKX...PHI...

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

LAT...LON   42837306 42167257 42037160 41727082 41237108 
            40707294 39957376 38377446 37327565 38147596 
            38677595 39137629 39447626 40007584 41097618 
            41937566 42447483