744  
AWUS01 KWNH 150201  
FFGMPD  
NYZ000-NJZ000-PAZ000-150630-  
 
MESOSCALE PRECIPITATION DISCUSSION 0662  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1001 PM EDT TUE AUG 14 2018  
 
AREAS AFFECTED...EASTERN NY/PA BORDER INTO NORTHWEST NJ  
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE  
 
VALID 150200Z - 150630Z  
 
SUMMARY...A FLASH FLOOD THREAT WILL LINGER FOR ANOTHER FEW HOURS  
ACROSS PORTIONS OF THE EASTERN NY/PA BORDER INTO NORTHEASTERN PA  
AND NORTHWESTERN NJ. LOCALIZED RAINFALL RATES PEAKING IN THE 1 TO  
1.5 IN/HR RANGE CAN BE EXPECTED WITH AN ADDITIONAL 2-3 INCHES  
EXPECTED BY 06-07Z, BEFORE DIMINISHING.  
 
DISCUSSION...KBGM RADAR IMAGERY OVER THE PAST 1-2 HOURS SHOWED  
RAINFALL RATES OF 1-2 IN/HR OVER BROOME AND SUSQUEHANNA COUNTIES  
CONFIRMED BY SURFACE OBSERVATIONS, SLOWLY TRANSLATING  
SOUTH-SOUTHEAST. CIRA LAYERED PW IMAGERY SHOWED THAT THE LINGERING  
AREA OF HEAVY RAINFALL RATES WAS OCCURRING WITHIN A REGION OF DEEP  
MOISTURE JUST WEST OF A MID-LEVEL LOW CENTERED OVER EASTERN NY AT  
01Z, CONNECTED TO A LARGER PLUME OF MOISTURE ADVANCING THROUGH NEW  
BRUNSWICK BY A NARROW RIBBON OF MOISTURE IN THE 700-500 MB LAYER.  
SPC MESOANALYSIS DATA FROM 01Z SHOWED MLCAPE ALONG THE EASTERN  
NY/PA BORDER WAS 500-1000 J/KG, COINCIDENT WITH THE ONGOING HEAVY  
RAIN.  
 
TRAINING ELEMENTS OF HEAVY RAIN REMAIN LIKELY GIVEN THAT AVERAGE  
STORM MOTIONS OFF TOWARD THE SOUTHEAST ARE EXCEEDED BY A POCKET OF  
STRONGER 850-700 MB NORTHWESTERLY FLOW NEAR 30 KT VIA AREA VAD  
WIND PLOTS. SHORT TERM RAP FORECASTS SHOW THE MID-LEVEL LOW  
ADVANCING INTO CENTRAL NEW ENGLAND BETWEEN 06-09Z WITH THE RIBBON  
OF HIGHER LOW-MID LEVEL MOISTURE TO THE WEST OF THE LOW CENTER AND  
CORRIDOR OF STRONGER 850-700 MB FLOW GRADUALLY LOWERING WHILE  
TRANSLATING INTO NORTHWEST NJ THROUGH 06Z.  
 
GIVEN 3-HOUR FLASH FLOOD GUIDANCE IS LARGELY AN INCH OR LESS ALONG  
THE EASTERN NY/PA BORDER INTO PORTIONS OF EASTERN PA AND NORTHWEST  
NJ, FLASH FLOODING WILL REMAIN POSSIBLE WITH ANY LOCAL FLARE UPS  
OF HEAVY RAIN, WITH THE THREAT LIKELY DIMINISHING BEYOND ABOUT 06Z  
AS UPPER FORCING BECOMES LESS FAVORABLE ALONG WITH FURTHER  
REDUCTIONS TO REMAINING CAPE.  
 
OTTO  
   
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...ALY...BGM...CTP...OKX...PHI...  
 
ATTN...RFC...MARFC...NERFC...  
 
LAT...LON 42767576 42677526 42507504 42087474 41747454  
41177412 40587438 40337492 40367550 40477603  
40737639 41197658 41837674 42337652 42637620  
 
 
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