031
AWUS01 KWNH 062233
FFGMPD
NYZ000-NJZ000-PAZ000-070400-
MESOSCALE PRECIPITATION DISCUSSION 0236
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
633 PM EDT TUE MAY 06 2025
AREAS AFFECTED...CENTRAL NY TO PA/NJ BORDER
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 062230Z - 070400Z
SUMMARY...ISOLATED TO WIDELY SCATTERED AREAS OF FLASH FLOODING
WILL REMAIN POSSIBLE ACROSS A BROAD SECTION OF UPSTATE NY DOWN TO
THE PA/NJ BORDER THROUGH 04Z. PEAK HOURLY RAINFALL UP TO 1.0-1.5
INCHES (ESPECIALLY EARLY ON) WILL BE LIKELY ON AN ISOLATED BASIS.
DISCUSSION...RADAR IMAGERY AT 2230Z SHOWED THAT A BROKEN LINE OF
SHOWERS/THUNDERSTORMS EXTENDED FROM NEAR SYRACUSE TO THE NY/PA/NJ
BORDER. A MESOSCALE AXIS OF LOW LEVEL CONVERGENCE TO THE WEST OF
SYRACUSE HAS RESULTED IN A LOCALIZED AREA OF HOURLY RAINFALL IN
EXCESS OF 2 INCHES (NORTH OF SKANEATELES) WITH SURROUNDING
LOCATIONS IN AND AROUND CENTRAL NY TO NORTHEASTERN PA, IN THE 1-2
INCH RANGE (IN 60 MINUTES). WATER VAPOR IMAGERY SHOWED A
WELL-DEFINED, NEGATIVELY TILTED SHORTWAVE TROUGH SWINGING TOWARD
THE NORTH OVER EASTERN PA, TO THE EAST OF A MID TO UPPER-LEVEL LOW
CENTER OVER NORTHWESTERN PA. FLOW AHEAD OF THIS FEATURE WAS
STRONGLY DIFFLUENT, AIDING IN LIFT WITHIN A WEAKLY UNSTABLE
AIRMASS (500-1000 J/KG MUCAPE), THOUGH INFRARED CLOUD TOPS HAVE
BEEN WARMING OVER THE PAST HOUR.
THROUGH 04Z, THE SHORTWAVE SPOKE IS FORECAST TO LIFT NORTHWARD
INTO CENTRAL NY, SENDING THE BROKEN CONVECTIVE LINE TOWARD THE
NORTH AND EAST INTO THE CATSKILLS AND HUDSON VALLEY. THERE IS A
LOW END THREAT FOR SOUTH TO NORTH TRAINING AS THE LINE ADVANCES
EAST, THOUGH ADVECTION OF DRIER AND MORE STABLE AIR INTO THE
REGION FROM THE SOUTHWEST SHOULD LESSEN THIS THE HEAVY RAIN/FLASH
FLOOD THREAT WITH TIME OVER EASTERN PORTIONS OF NY.
OVER CENTRAL NY, WEAKER DEEPER LAYER MEAN FLOW WILL CONTINUE TO BE
SUPPORTIVE OF SLOWER MOVEMENT OF HEAVY RAIN CORES WITH THE ONGOING
AXIS WEST OF SYRACUSE EXPECTED TO ADVANCE OFF TOWARD THE NORTHEAST
OVER THE NEXT COUPLE OF HOURS. MEANWHILE ADDITIONAL HEAVY RAIN MAY
MOVE IN FROM THE SOUTH THROUGH 04Z WITH PEAK RAINFALL RATES
LOWERING INTO THE 0.5 TO 1.0 IN/HR RANGE AS INSTABILITY DIMINISHES
WITH THE LOSS OF DAYTIME HEATING. AN ADDITIONAL 1-2 INCHES OF RAIN
(LOCALLY A LITTLE ABOVE 2 INCHES OVER CENTRAL NY) IS EXPECTED ON A
LOCALIZED BASIS WHICH MAY LINGER THE FLASH FLOOD THREAT FOR
ANOTHER FEW HOURS OVER NORTHERN PA/NJ INTO NY.
OTTO
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ALY...BGM...BTV...BUF...CTP...OKX...PHI...
ATTN...RFC...MARFC...NERFC...NWC...
LAT...LON 44567573 44147450 43527391 42747368 41367401
41047446 41057510 41407572 41577626 41877770
42487817 43287778 44027718 44467636
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