Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 311904 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 304 PM EDT THU JUL 31 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TONIGHT AND CONTINUES TO DRIFT TO THE NORTHEAST ON FRIDAY. LOW PRESSURE APPROACHES FROM THE SOUTH FRIDAY NIGHT. A FRONTAL BOUNDARY OVER THE ATLANTIC COAST WILL IMPACT THE AREA THROUGH THE BEGINNING OF THE WEEK. HIGH PRESSURE THEN BUILDS INTO THE REGION ON TUESDAY AND REMAINS THROUGH THURSDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... SFC HIGH PRES OVER THE MID-ATLANTIC MOVES OFFSHORE TONIGHT. MEANWHILE...A WEAK H5 SHORTWAVE MOVES THROUGH THE REGION THIS EVENING. SOME SHOWERS AND TSTMS HAVE DEVELOPED OVER EASTERN PA AND ARE MOVING TOWARDS NJ AND THE LOWER HUDSON VALLEY. INSTABILITY VALUES ARE FAIRLY HIGH...WITH ML MUCAPE VALUES AVERAGING 500-750 J/KG ACROSS MOST OF THE REGION...AND OVER 1000 J/KG ACROSS NORTHERN PORTIONS OF THE LOWER HUDSON VALLEY. THERE IS ALSO 30-40 KT OF 0-6 KM BULK SHEAR ACROSS NYC AND LONG ISLAND AND 40-50 KT OF 0-6 KM BULK SHEAR ACROSS THE INTERIOR. HOWEVER...THERE IS LITTLE LIFT IN THE ATMOSPHERE AS MOST OF THE ENERGY REMAINS NORTH OF THE REGION AND THE LIFTED INDEX RANGES FROM 0 TO -2C. SOME OF THOSE SHOWERS COULD MAKE IT INTO THE LOCAL AREA THROUGH THIS EVENING...BUT DO THINK THINK COVERAGE WILL BE WIDESPREAD. WILL CONTINUE TO CARRY SLIGHT CHANCE POPS FOR NE NJ...NYC...THE LOWER HUDSON VALLEY...AND SW CT. THE MARINE LAYER WILL BE STRONG ENOUGH TO KEEP STORMS ROM DEVELOPING ACROSS EASTERN LONG ISLAND AND SE CT. ANY SHOWERS WILL QUICKLY TAPER OFF AROUND SUNSET. WITH SOUTHERLY FLOW AND INCREASING LOW-LEVEL MOISTURE...WILL EXPECT PATCHY FOG TO DEVELOP AFTER MIDNIGHT TONIGHT. LOWS WILL DROP INTO THE UPPER 60S TO AROUND 70 IN/AROUND NYC...AND GENERALLY IN THE LOW TO MID 60S ELSEWHERE. FAR NW PORTIONS OF ORANGE COUNTY COULD DROP INTO THE MID 50S. THERE REMAINS A MODERATE RISK FOR RIP CURRENTS INTO THIS EVENING. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... DEEP UPPER TROUGH DIGS INTO THE GREAT LAKES/OHIO VALLEY ON FRIDAY... AND SEVERAL SHORTWAVES WILL SLIDE ALONG THE COAST AND INTO THE LOCAL AREA DURING THE DAY. WITH INCREASED MOISTURE...SFC DEW POINTS WILL CLIMB INTO THE LOW-MID 60S...AND HIGHER INSTABILITY LEVELS...CAN EXPECT MORE DIURNALLY DRIVEN SHRA/TSTMS TO DEVELOP DURING THE DAY. BEST CHANCES FOR THIS ACTIVITY WILL BE ACROSS NYC/NE NJ/LOWER HUDSON VALLEY/SW CT. 0-6KM BULK SHEAR WILL AVERAGE 20-30 KT...SO NOT EXPECTING STORMS TO BE TOO LONG LIVED...BUT UPPER LEVEL FLOW IS WEAK...SO STORMS THAT DEVELOP WILL BE SLOW TO DEPART. THIS COULD RESULT IN THE POTENTIAL FOR LOCALIZED URBAN/POOR DRAINAGE FLOODING. SHOWERS/STORMS TAPER OFF FRIDAY EVENING. LOW PRES DEVELOPING OVER THE MID-ATLANTIC WILL LIFT NORTH FRIDAY NIGHT...BRINGING SHOWERS TO THE REGION TOWARDS DAYBREAK SATURDAY. HIGHS ON FRIDAY WILL MODERATE TO NEAR NORMAL LEVELS...TOPPING OFF IN THE LOW TO MID 80S...WITH TEMPS IN THE MID 80S ACROSS NYC/NE NJ. && .LONG TERM /SATURDAY THROUGH THURSDAY/... HIGH PRESSURE IS EXPECTED TO LIFT TO THE NORTHERN ATLANTIC WHILE A COASTAL FRONT REMAINS ALONG THE EAST COAST. A SOUTHERLY FLOW WILL CONTINUE TO DRAW MOISTURE INTO THE AREA RESULTING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS NEAR OR OVER THE AREA THROUGH THE WEEKEND. A WEAK FRONT WILL MOVE ACROSS THE AREA SUNDAY NIGHT INTO MONDAY AND SHOWERS SHOULD TAPPER OFF BY MONDAY AFTERNOON. DRY WEATHER RETURNS TUESDAY AND REMAINS THROUGH THE END OF THE EXTENDED PERIOD. TEMPERATURES FOR THE WEEKEND WILL BE SLIGHTLY BELOW NORMAL... HOWEVER TEMPERATURES BOUNCE BACK FOR THE BEGINNING OF THE WEEK... WITH HIGHS IN THE LOWER 80S AND LOW IN THE UPPER 60S...WHICH IS NEAR NORMAL FOR THIS TIME OF YEAR. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... HIGH PRESSURE WILL REMAIN OFFSHORE INTO FRIDAY AFTERNOON. VFR THROUGH THE TAF PERIOD. CONVECTIVE POTENTIAL HAS APPEARED TO DECREASE ACROSS THE REGION THIS AFTERNOON...SO HAVE REMOVED TEMPO GROUP FOR SHRA AT KSWF. WHILE CANNOT COMPLETELY RULE OUT A SHRA/TSTM AT CITY AND WESTERN TERMINALS...THE PROBABILITY OF OCCURRENCE AT ANY GIVEN TERMINAL IS 10 PERCENT OR LESS. SW WINDS VEER TO THE S AND INCREASE INTO THE AFTERNOON...AND WILL BE GUSTY AT CITY TERMINALS...WITH A SEABREEZE COMPONENT. WINDS BECOME LIGHT AND VARIABLE THIS EVENING...THEN INCREASE OUT OF THE S-SE MID-LATE FRIDAY MORNING. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: TIMING OF START/END OF GUSTY WINDS THIS AFTERNOON AND LIGHT AND VARIABLE WINDS THIS EVENING COULD BE OFF +/- 1-2 HOURS. KLGA FCSTER COMMENTS: TIMING OF THE END OF GUSTY WINDS THIS AFTERNOON AND START/END OF LIGHT AND VARIABLE WINDS THIS EVENING COULD BE OFF +/- 1-2 HOURS. KEWR FCSTER COMMENTS: TIMING OF THE END OF GUSTY WINDS THIS AFTERNOON AND START/END OF LIGHT AND VARIABLE WINDS THIS EVENING COULD BE OFF +/- 1-2 HOURS. KTEB FCSTER COMMENTS: TIMING OF THE END OF GUSTY WINDS THIS AFTERNOON AND START/END OF LIGHT AND VARIABLE WINDS THIS EVENING COULD BE OFF +/- 1-2 HOURS. KHPN FCSTER COMMENTS: TIMING IN CHANGES IN WIND DIRECTION/SPEED COULD BE OFF +/- 1-2 HOURS. KISP FCSTER COMMENTS: TIMING IN CHANGES IN WIND DIRECTION/SPEED COULD BE OFF +/- 1-2 HOURS. .OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY... .FRIDAY-FRIDAY NIGHT...MAINLY VFR. ISOLD SHRA/TSTMS POSSIBLE IN THE AFTERNOON/EVENING. .SATURDAY-SUNDAY NIGHT...AREAS OF MVFR OR LOWER POSSIBLE. .MONDAY-TUESDAY...MAINLY VFR. ISOLD SHRA/TSTMS POSSIBLE IN THE AFTERNOON/EVENING. && .MARINE... SUB-SMALL CRAFT ADVISORY CONDS EXPECTED ON THE WATERS THROUGH NEXT THURSDAY. && .HYDROLOGY... NO SIGNIFICANT RAINFALL IS EXPECTED THROUGH TONIGHT. LOCALLY HEAVY DOWNPOURS IN SCATTERED TSTMS ON FRIDAY WILL PRESENT MAINLY A URBAN/POOR DRAINAGE FLOOD THREAT DUE TO SLOW MOVEMENT... WITH A LOW AND LOCALIZED FLASH FLOOD THREAT WITH ANY TRAINING OF CELLS. AN INCREASINGLY MOIST AIR MASS WILL BE CONDUCIVE TO THE DEVELOPMENT OF HEAVY SHOWERS THIS WEEKEND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...FIG/MPS NEAR TERM...MPS SHORT TERM...MPS LONG TERM...FIG AVIATION...MALOIT MARINE...FIG/MPS HYDROLOGY...FIG/MPS

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