MESOSCALE PRECIPITATION DISCUSSION 0439
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
234 PM EDT FRI JUL 08 2016
 
AREAS AFFECTED...EASTERN PA...NORTHEAST MD...NORTHERN
DE...NJ...SOUTHEAST NY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 081830Z - 090000Z
 
SUMMARY...CLUSTERS OF THUNDERSTORMS ARE EXPECTED TO EXPAND IN
COVERAGE THIS AFTERNOON. INTENSE RAINFALL RATES UP TO 2 INCHES/HR
MAY RESULT IN SOME FLASH FLOODING.

DISCUSSION...AN MCV CROSSING WESTERN NY EARLY THIS AFTERNOON ALONG
WITH THE SOUTHWARD EXTENSION OF A MID LEVEL TROUGH AXIS DOWN
THROUGH CENTRAL PA WILL HELP ENHANCE COVERAGE THROUGH THE
AFTERNOON OF HEAVY SHOWERS AND THUNDERSTORMS. DIABATIC HEATING IS
CONTRIBUTING TO MLCAPE VALUES OF 1000 TO 1500 J/KG...WHICH SHOULD
INCREASE A BIT MORE THROUGH THE MID-AFTERNOON HOURS. THE
CONVECTION SHOULD TEND TO ORGANIZE INTO MULTIPLE CLUSTERS OF CELLS
THAT WILL BE CAPABLE OF PRODUCING INTENSE RAINFALL RATES OF UP TO
2 INCHES/HR GIVEN THE HIGH PWAT ENVIRONMENT ACROSS THE
MID-ATLANTIC AND SOUTHERN NEW ENGLAND.

HIRES GUIDANCE LED BY THE LATEST WRF-ARW AND WRF-NMMB SUGGEST
RAINFALL POTENTIAL OF 2 TO 4 INCHES...WITH THE HEAVIEST AMOUNTS
FOCUSING OVER SOUTHEAST NY AND ACROSS NJ WHERE THERE IS PROXIMITY
OF A STATIONARY FRONT. FRONTAL CONVERGENCE COUPLED WITH THE
POOLING OF MOISTURE AND INSTABILITY ALONG AND WEST OF THE I-95
CORRIDOR WILL FAVOR THE CONCENTRATION OF HEAVIER RAINFALL FOR
THESE AREAS. SOME FLASH FLOODING WILL BE POSSIBLE GIVEN THE
EXPECTED HEAVY RAINFALL RATES AND GRADUAL ORGANIZATION AND
CONCENTRATION OF CONVECTIVE CELLS.

ORRISON

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

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

LAT...LON   42787491 42787371 42227345 41157381 40377399 
            39477464 38907554 39047657 39447691 40027694 
            41167638 42067573