MESOSCALE PRECIPITATION DISCUSSION 0453
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
525 AM EDT SAT JUL 08 2017

AREAS AFFECTED...CENTRAL/NORTHEAST NY...VT...NH...WESTERN ME

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

VALID 080925Z - 081525Z

SUMMARY...SCATTERED CLUSTERS OF HEAVY SHOWERS AND THUNDERSTORMS
THIS MORNING MAY RESULT IN SOME POCKETS OF RUNOFF PROBLEMS AND
FLASH FLOODING.

DISCUSSION...A FAIRLY STRONG SHORTWAVE TROUGH AND AN ATTENDANT
COLD FRONT WILL BE CROSSING THE LOWER GREAT LAKES REGION THIS
MORNING AND ADVANCING THROUGH NY STATE AND INTERIOR SECTIONS OF
NEW ENGLAND THROUGH MIDDAY. ALREADY THE DYNAMICS ASSOCIATED WITH
THIS COUPLED WITH A NOSE OF MODEST INSTABILITY POOLING UP ACROSS
WESTERN NY IS HELPING TO FOSTER SEVERAL CLUSTERS OF PROGRESSIVE
THUNDERSTORM ACTIVITY. IN FACT...THE LATEST RAP ANALYSIS SHOWS A
90+ KT 250 MB JET MAX NOW LIFTING UP ACROSS WESTERN NY AND TOWARD
CENTRAL/NORTHERN VT WHILE A POOL OF 500 TO 1000 J/KG OF MUCAPE IS
POOLED ALONG AND JUST AHEAD OF THE COLD FRONT MOVING INTO WESTERN
NY.

THE ANTECEDENT SOIL CONDITIONS ACROSS MUCH OF CENTRAL/NORTHEAST NY
AND INTO THE NORTHERN APPALACHIANS INCLUDING THE GREEN AND WHITE
MOUNTAINS OF VT/NH...AND WESTERN ME ARE QUITE MOIST OWING TO
MULTIPLE HEAVY RAINFALL EVENTS OVER THE LAST WEEK.

RAINFALL RATES OF 1 TO 1.5 INCHES/HR WILL BE POSSIBLE...WITH LOCAL
TOTALS OF 2 TO 2.5 INCHES NOT OUT OF THE QUESTION ACROSS THE MPD
THREAT AREA AS THUNDERSTORMS LIFT NORTHEAST UP ALONG AND AHEAD OF
THE COLD FRONT THROUGH MIDDAY. CONDITIONS WILL THEN IMPROVE AS THE
FRONT SWEEPS EAST AND ALLOWS DRIER AIR TO GRADUALLY ARRIVE FROM
THE WEST.

HOWEVER...THE ADDITIONAL THUNDERSTORM ACTIVITY THIS MORNING WITH
THESE HEAVIER RAINFALL RATES OCCURRING OVER MOUNTAINOUS TERRAIN
WILL ENCOURAGE SOME ADDITIONAL SHORT-TERM RUNOFF AND/OR FLASH
FLOODING CONCERNS. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...ALY...BGM...BTV...BUF...CAR...GYX...

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

LAT...LON   47196899 46846871 45926890 44886971 44187040
            43397151 43027265 42717427 42547549 42477652
            42537758 42777805 43107808 43247782 43287715
            43477665 43627633 44167627 44427595 44827520
            45117422 45107326 45317176 45647096 46107041
            46996965