Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 292201 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 601 PM EDT FRI MAY 29 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE ATLANTIC THROUGH SATURDAY AFTERNOON. A COLD FRONT WILL APPROACH SATURDAY NIGHT...AND MOVE THROUGH ON SUNDAY. THE FRONT WILL STALL JUST TO THE SOUTH AS WEAK LOW PRESSURE RIDES ALONG IT. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH LATE TUESDAY INTO WEDNESDAY...AND SHIFT TO THE SOUTH ON THURSDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AFTER A MOSTLY SUNNY AFTERNOON...WITH ONLY A FEW CU OVER INTERIOR SE CT AND THIN HIGH CLOUDS FROM NYC NORTH/WEST...ATTENTION WILL TURN TO DEVELOPMENT OF LOW STRATUS AND PATCHY FOG TONIGHT. PATCH OF LOW CLOUDS 20-40 NM S OF SUFFOLK COUNTY HAS BEEN SLOWLY EXPANDING. COMBO OF ONSHORE FLOW AND LOW LEVEL RADIATIONAL COOLING UNDER CLEAR SKIES WILL PROMOTE ITS EXPANSION NORTH/WEST AFTER DARK...TO THE SOUTH SHORE OF LONG ISLAND AND POSSIBLY COASTAL SE CT BY LATE EVENING...THEN INTO THE REST OF LONG ISLAND AND SOUTHERN CT AFTER MIDNIGHT AND POSSIBLY ALL AREAS LATE TONIGHT. LOW TEMPS WILL BE IN THE UPPER 50S ACROSS ERN LONG ISLAND AND SE CT...LOWER 60S MOST ELSEWHERE...AND MID 60S INVOF NYC. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... MORNING LOW CLOUDS SHOULD BE SLOW TO BURN OFF ESPECIALLY ACROSS LONG ISLAND AND COASTAL CT. SFC RIDGING AND SOUTHERLY FLOW SHOULD KEEP THE AIR MASS STABLE OVER MOST OF THE CWA FROM NYC EAST... WHILE ENOUGH LATE DAY INSTABILITY MAY DEVELOP WELL NORTH/WEST OF NYC AHEAD OF AN ADVANCING WEAK SHORTWAVE TO SPARK ISOLD-SCT SHOWERS AND POSSIBLY A TSTM. AFTERNOON COASTAL SEA BREEZES WILL BE ENHANCED BY A TIGHT PRESSURE GRADIENT...AND COULD AGAIN SEE GUSTS 20-30 MPH LATE IN THE AFTERNOON ESPECIALLY ACROSS LONG ISLAND. HIGH TEMPS SHOULD BE 80-85 INLAND AND IN THE 70S ALONG THE COAST. CONVECTIVE POTENTIAL SHOULD WANE SAT EVENING WITH LOSS OF DAYTIME HEATING...THEN COULD SEE SCT SHOWERS AND POSSIBLY A TSTM LATE AT NIGHT AS A COLD FRONT APPROACHES. PREFER SLIGHTLY SLOWER/DRIER FRONTAL APPROACH PER NAM/ECMWF VS FASTER/WETTER GFS...AND SO HAVE SCALED BACK GUIDANCE POP...WITH ONLY CHANCE LATE AT NIGHT MAINLY INLAND. LOW TEMPS SHOULD BE IN THE LOWER AND MID 60S. THERE IS A HIGH RISK OF RIP CURRENTS AT THE ATLANTIC BEACHES SATURDAY. STRONGEST RIP CURRENTS WOULD OCCUR DURING THE AFTERNOON AS THE SOUTHERLY WINDS INCREASE. && .LONG TERM /SUNDAY THROUGH FRIDAY/... COLD FRONT SLOWLY CROSSES THROUGH THE CWA THROUGH ON SUNDAY WITH SHOWERS BECOMING LIKELY. CAPE IS SUFFICIENT FOR A CHANCE OF THUNDERSTORMS. WITH THE COLD FRONT BECOMING ALIGNED WITH THE UPPER FLOW ALONG WITH A RELATIVELY SLOW STORM MOTION FORECAST...WILL NEED TO KEEP AN EYE OUT FOR THE POTENTIAL OF TRAINING CELLS AND AT LEAST MINOR URBANIZED/SMALL STREAM FLOODING DURING THE AFTERNOON AND EVENING HOURS. THE COLD FRONT STALLS TO OUR SOUTH...THEN A WAVE OF LOW PRESSURE FORMS ALONG IT...PASSING OVER OR JUST SOUTH OF US ON TUESDAY. MODELS DISAGREE ON HOW QUICKLY THIS HAPPENS WITH ECMWF CONTINUING TO BE THE SLOWEST WITH THE PASSAGE. HAVE GONE WITH LIKELY POPS THROUGH MONDAY NIGHT BEFORE TAPERING TO CHC ON TUESDAY. MIGHT EVENTUALLY NEED TO INCREASE POPS FOR TUESDAY...ESPECIALLY OVER EASTERN ZONES. ELEVATED CAPE WILL BE JUST SOUTH OF US...SO NO MENTION OF THUNDER FROM LATE SUNDAY NIGHT THROUGH TUESDAY. AFTER NEAR-NORMAL HIGHS ON SUNDAY...MONDAY AND TUESDAY SHOULD BE BELOW NORMAL WITH RAIN/CLOUDS/ONSHORE FLOW. WILL MAINTAIN A DRY FORECAST FOR WEDNESDAY...FAVORING THE MORE PROGRESSIVE MODELS. HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING LOW. HIGHER CONFIDENCE THAT THURSDAY WILL BE DRY WITH THE CENTER OF THE HIGH PASSING THROUGH. TEMPS RETURNING TO NORMAL. FRIDAY LIKELY REMAINS DRY AS WELL WITH THE HIGH OFFSHORE AND THE NEXT COLD FRONT WELL OFF TO THE NW. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... HIGH PRESSURE REMAINS OFFSHORE THROUGH SATURDAY WITH A COLD FRONT APPROACHING FROM THE GREAT LAKES. THIS WILL KEEP THE AREA UNDER A PROLONGED PERIOD OF SOUTHERLY FLOW. FORECAST DILEMMA RESIDES IN THE EXTENT AND MAGNITUDE OF STRATUS/FOG DEVELOPMENT TONIGHT. LATEST SAT IMAGERY SHOWS AREA OF STRATUS 40-50 MILES SOUTH OF LI. THIS WILL BEGIN RETURNING NORTH THIS AFT AS WINDS BECOMES SE...AND MAY REACH THE SOUTH SHORE BETWEEN 00Z AND 03Z. THE OFFSETTING FACTOR WITH BE THE AMOUNT OF DRY AIR OVER LAND. THUS...HAVE DELAYED IFR/MVFR CONDITIONS UNTIL AFTER 06Z TONIGHT...AND THEN QUICKLY IMPROVE TO VFR AFTER 12Z SAT. 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 STRATUS ALONG THE SOUTH SHORE COULD MOVE IN EARLIER THIS EVENING. KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KISP FCSTER COMMENTS: TIMING OF STRATUS ALONG THE SOUTH SHORE COULD MOVE IN EARLIER THIS EVENING. .OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... .SATURDAY AFTERNOON...MOST LIKELY VFR. CHANCE OF MVFR IN SHOWERS/THUNDERSTORMS MAINLY TO THE N/W OF CITY TERMINALS. GUSTS TO 20-25KT POSSIBLE WITH SEA BREEZE. .SATURDAY NIGHT-TUESDAY MORNING...MVFR OR LOWER AT TIMES IN SHOWERS. THUNDERSTORMS POSSIBLE SATURDAY NIGHT-SUNDAY NIGHT. .TUESDAY AFTERNOON/NIGHT...BECOMING VFR. .WEDNESDAY...VFR. && .MARINE... QUIET CONDS THROUGH EARLY SAT AFTERNOON. COASTAL SEA BREEZES ENHANCED BY A TIGHTENING PRESSURE GRADIENT SHOULD THEN HELP GENERATE FREQUENT GUSTS UP TO 25 KT ALONG THE NEAR SHORE WATERS SOUTH OF LONG ISLAND LATE SAT AFTERNOON INTO SAT EVENING...SO HAVE RAISED SCA FOR THE OCEAN AND THE SOUTH SHORE BAYS. OCEAN SEAS MAY FLIRT WITH 5 FT LATE SAT AFTERNOON AND SAT NIGHT. WITH SUSTAINED WINDS REMAINING MOSTLY 15 KT OR LESS HELD THEM AT 4 FT. SCA CONDS WILL PROBABLY BE ON THE OCEAN WATERS SUNDAY AND SUNDAY NIGHT...HOWEVER THERE COULD BE AN EXTENDED PERIOD DURING THIS TIME FRAME WHERE THE CRITERIA IS NOT BEING MET. E WINDS OTHERWISE INCREASE ON MONDAY WITH SCA CONDS PROBABLE ON MOST OF THE WATERS. WINDS THEN SUBSIDE ON TUESDAY...BUT A LINGERING SWELL MAY KEEP OCEAN SEAS AT SCA LEVELS THROUGH THE DAY...AND PROBABLY THROUGH MOST OF WED AS WELL. && .HYDROLOGY... FORECAST RAIN AMOUNTS FROM SUNDAY THROUGH MONDAY NIGHT CURRENTLY RANGE FROM 1.5 TO 2.5 INCHES. AS USUAL...LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE DUE TO SCATTERED THUNDERSTORMS. THESE THUNDERSTORMS ARE MORE LIKELY TO OCCUR SUNDAY AFTERNOON AND EVENING. THERE IS A THREAT OF FLOODING...BUT MINOR URBAN/POOR DRAINAGE/SMALL STREAM FLOODING WOULD BE MORE LIKELY. FLASH FLOODING IS NOT OUT OF THE QUESTION SUNDAY AFTERNOON AND NIGHT...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE HAZARDOUS WEATHER OUTLOOK...ESPECIALLY WITH ANTECEDENT DRY CONDITIONS FOR THE PAST MONTH OR SO. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 PM TO 11 PM EDT SATURDAY FOR ANZ345-350-353-355. && $$ SYNOPSIS...JC/GOODMAN NEAR TERM...GOODMAN SHORT TERM...GOODMAN LONG TERM...JC AVIATION...DW MARINE...JC/GOODMAN HYDROLOGY...JC

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