MESOSCALE PRECIPITATION DISCUSSION 0432
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
218 PM EDT THU JUL 07 2016
 
AREAS AFFECTED...SOUTHEAST NY/LONG
ISLAND...NJ...CT...RI...CENTRAL/WESTERN MA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 071815Z - 072300Z
 
SUMMARY...SLOW-MOVING CONVECTIVE CELLS WILL TEND TO EXPAND A BIT
MORE IN COVERAGE OVER THE NEXT COUPLE OF HOURS. INTENSE RAINFALL
RATES OF UP TO 1.5 INCHES/HR MAY RESULT IN SOME FLASH FLOODING.

DISCUSSION...EARLY-AFTERNOON VIS IMAGERY CONFIRMS THE PRESENCE OF
A WEAK LOW TO MID LEVEL VORT CENTER/TROUGH EXTENDING FROM
NORTHEAST PA UP INTO SOUTH-CENTRAL NY. AHEAD OF THIS ENERGY IS A
MODERATELY UNSTABLE AIRMASS OVER SOUTHEAST NY...CENTRAL AND
WESTERN CT AND SOUTHWEST MA...WITH MLCAPE VALUES APPROACHING 2000
J/KG. CONVECTION IS ALREADY EXPANDING IN COVERAGE WITH SLOW CELL
MOTION OFF TO THE EAST-NORTHEAST.

HIGH PWATS REACHING TO NEAR 2 INCHES IS POOLING ACROSS THE REGION
AHEAD OF THE AFOREMENTIONED SHORTWAVE WHICH IS ADVANCING EAST
TOWARD THE I-95 CORRIDOR. OVER THE NEXT COUPLE OF HOURS...THE
GUIDANCE INDICATES THE DEVELOPMENT OF A WELL-DEFINED LEE-SIDE
TROUGH ALONG THE I-95 CORRIDOR AND EXTENDING SOUTH FROM SURFACE
LOW PRESSURE MOVING INTO CENTRAL NEW ENGLAND. THE PRESSURE FALLS
WILL ONLY HELP CONCENTRATE DEEPER MOISTURE/INSTABILITY ACROSS THE
THREAT AREA...AND WILL FOSTER MORE EXPANSIVE CONVECTIVE
DEVELOPMENT.

GIVEN THE HIGHER PWATS AND SLOW MOVEMENT OF THE CONVECTIVE
CELLS...HEAVY RAINFALL TOTALS ARE EXPECTED..AND ESPECIALLY NEAR
AREAS OF HIGHER TERRAIN WITH THE AID OF OROGRAPHIC ASCENT. THE
HIRES GUIDANCE DOES NOT NECESSARILY FOCUS MUCH IN THE WAY OF
ORGANIZED CONVECTION THIS AFTERNOON...BUT THE AFOREMENTIONED
PRESSURE FALLS AND N/S TROUGH AXIS FOCUSING DEEPER
MOISTURE/INSTABILITY SUGGESTS THAT CONVECTION MAY INDEED BECOME
MORE CONCENTRATED AND ORGANIZED.

EXPECT AS MUCH AS 3 TO 4 INCHES OF RAIN AT LEAST LOCALLY...AND
THIS WILL FOSTER SOME FLASH FLOODING POTENTIAL.

ORRISON/GALLINA

ATTN...WFO...ALY...BGM...BOX...GYX...OKX...PHI...

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

LAT...LON   42947318 42777234 42137166 41917101 41477088 
            41237132 40817254 40527339 39837406 39437424 
            39397443 39687458 39817473 40727483 42067455 
            42627416