Mesoscale Precipitation Discussion 901
NWS Weather Prediction Center College Park MD
836 PM EDT Wed Sep 26 2018

Areas affected...Southeast NY...Connecticut...Rhode
Island...Southern MA

Concerning...Heavy rainfall...Flash flooding possible

Valid 270034Z - 270404Z

Summary...Line of heavy showers and thunderstorms approaching
southern New England will affect areas that received torrential
downpours and flooding within the past two days.  Flash flooding
will be possible with some of the strongest storms this evening.

Discussion...Regional radar imagery is depicting an organized band
of heavy showers and storms approaching the greater New York City
area as of 8:30pm local time ahead of a cold front.  Although this
activity is progressive towards the east, the storms are expected
to cross over areas that had flash flooding on Tuesday afternoon. 
Given saturated ground conditions, especially north of Long Island
Sound, any additional downpours in excess of an inch per hour
could lead to additional flooding concerns. 

The latest high res model suite is indicating the potential for up
to two inches of rainfall by midnight from the strongest
convective cells, with the WRF showing some of the higher amounts.
 These amounts seem reasonable given the surge of 2 inch PWs ahead
of the front as depicted by the latest RAP model analysis.  This
band of showers and storms should exit the coast by midnight and
the flash flood threat should be over by then.

D. Hamrick

ATTN...WFO...ALY...BOX...OKX...PHI...

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

LAT...LON   42517192 42437081 42157008 41806977 41326983
            41127009 41027087 40937184 40657262 40517335
            40517399 40687456 41027479 41627425 42297355
            42487314