Flash Flood Guidance
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000
AWUS01 KWNH 170204
FFGMPD
MEZ000-MAZ000-NHZ000-170601-

MESOSCALE PRECIPITATION DISCUSSION 0427
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1002 PM EDT THU OCT 16 2014

AREAS AFFECTED...EASTERN MA/MOST OF MAINE...

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 170201Z - 170601Z

SUMMARY...ANOMALOUS TROPOSPHERIC MOISTURE CONTENT WILL CONTINUE TO
BOMBARD NEW ENGLAND INTO THE OVERNIGHT HOURS WITH HOURLY RAINFALL
RATES EXPECTED TO REACH THE 1 TO 1.50 INCH RANGE AT TIMES.
RELATIVELY HIGH FFG VALUES SHOULD LIMIT THE THREAT OF A WIDESPREAD
FLASH FLOODING EVENT.

DISCUSSION...A STRONG UPPER LOW CURRENTLY LIFTING THROUGH THE
LOWER GREAT LAKES CONTINUES TO ADVECT ENHANCED MOISTURE FROM DEEP
IN THE TROPICS. ADDITIONALLY...WATER VAPOR IMAGERY AND THE
BLENDED-TPW PRODUCT INDICATES THERE IS A CONNECTION TO HURRICANE
GONZALO WHICH IS CURRENTLY SOUTH OF BERMUDA. THIS HAS RAISED THE
PWAT VALUES TO NEARLY 3 STANDARD DEVIATIONS ABOVE NORMAL OVER MUCH
OF NEW ENGLAND BASED ON THE 00Z RAOBS. LOOKING MORE CLOSELY AT THE
00Z SOUNDING FROM GYX...AS EXPECTED...A HEAVY RAINFALL PROFILE IS
NOTED WITH STRONG UNIDIRECTIONAL FLOW...TALL/SKINNY CAPE...AND
FREEZING LEVELS EXTENDING UP TO NEAR 12500 FT INDICATIVE OF WARM
RAIN PROCESSES DOMINATING. THE HOURLY RAINFALL RATES HAVE BEEN
AROUND 1 TO 1.50 INCHES WITH SUCH VALUES EXPECTED TO CONTINUE
DURING THE NEXT SEVERAL HOURS. THE HIGH-RESOLUTION GUIDANCE
SUGGESTS 2 TO 3 INCHES OF RAINFALL CAN BE EXPECTED THROUGH 06Z ON
A BROADER SCALE WITH LOCALIZED HEAVIER AMOUNTS LIKELY GIVEN THE
IMPRESSIVE MOISTURE CONTENT IN PLACE. WILL REASSESS THE SITUATION
AFTER 06Z TO SEE IF AN ADDITIONAL MPD IS NEEDED OVERNIGHT.


RUBIN-OSTER

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BOX...CAR...GYX...

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

LAT...LON   47496910 46766849 44316857 41966812 40966843
            40496894 40376985 40897095 42317094 43297088
            46047116 46957103 47457026



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