MESOSCALE PRECIPITATION DISCUSSION 0484
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1042 AM EDT THU JUL 13 2017

AREAS AFFECTED...CNTRL/WRN NY INTO NRN PA

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

VALID 131439Z - 132000Z

SUMMARY...RAINFALL RATES OF 1-2 IN/HR WILL POSE A FLASH FLOOD
THREAT OVER THE NEXT FEW HOURS FROM WRN AND CNTRL NY INTO FAR NRN
PA.

DISCUSSION...14Z EXPERIMENTAL GOES 16 INFRARED IMAGERY SHOWED A
PERSISTENT REGION OF COLDER CLOUD TOPS OVER GENESEE AND WYOMING
COUNTIES OF WRN NY...CONTAINED WITHIN A BROADER...MORE STRATIFORM
REGION OF RAINFALL EXTENDING FROM NWRN PA TOWARD LAKE ONTARIO.
RECENT RAINFALL RATES BENEATH THESE COLDER CLOUD TOPS WERE IN THE
1-2 IN/HR RANGE ACROSS THE BUFFALO METRO AREA AND ALONG A
STATIONARY FRONT EXTENDING WEST TO EAST ACROSS WRN AND CNTRL NY.
NORTH TO SOUTH TEMPERATURE/DEWPOINT CONTRAST ACROSS THE STATIONARY
FRONT WAS RATHER SHARP FOR 14Z...WITH 10-15F/5-10F NOTED IN 14Z
OBSERVATIONS RESPECTIVELY. DUE TO EXTENSIVE CLOUD COVER OVER CNTRL
NY AND NRN PA ALONG WITH MARGINAL 700-500 MB LAPSE RATES OF
ROUGHLY 6 TO 6.5 C/KM...MLCAPE IS LIMITED ACROSS THE REGION AND
CONFINED TO LOCATIONS ALONG AND SOUTH OF THE STATIONARY FRONT WITH
AN ESTIMATED 500-1000 J/KG BASED ON 12Z RAOB DATA.

AN MCV WAS IDENTIFIED NEAR ERI...TRACKING TOWARD THE EAST...NEARLY
COINCIDENT WITH THE STATIONARY FRONT. ENHANCED LOW LEVEL MOISTURE
FLUX INTO THE FRONTAL BOUNDARY ALONG WITH MEAN STORM MOTIONS
PARALLELING THE FRONT SHOULD ALLOW FOR NEW DEVELOPMENT OVER CNTRL
NY WITHIN THE NEXT 1-2 HOURS AND CONTINUED TRAINING OF 1-2 IN/HR
RAINFALL RATES INTO THE AFTERNOON DESPITE FORECAST LIMITED
INCREASES IN MLCAPE. GIVEN FLASH FLOOD GUIDANCE OF GENERALLY 1-2
IN/HR IS IN PLACE ACROSS MUCH OF CNTRL AND WRN NY...FLASH FLOODING
WILL BE POSSIBLE.

OTTO

ATTN...WFO...ALY...BGM...BUF...CTP...

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

LAT...LON   43197598 43077400 42557346 41907385 41597580
            41807799 42157902 42607918 43057805