Area Forecast Discussion
Issued by NWS Upton, NY

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745 FXUS61 KOKX 221324 AFDOKX Area Forecast Discussion National Weather Service New York NY 924 AM EDT Sun Oct 22 2017 .SYNOPSIS... Dry and mild today as high pressure pulls away from the region. The weather then becomes rather unsettled for Tuesday and Wednesday with potentially heavy rain. Relatively strong gust winds are likely on Tuesday. Dry weather returns for late week into the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Unseasonably warm and fair weather continue today. Just some cirrus filtering sunshine, with temps still about 15 degrees above normal in the mid to upper 70s. Temps are expected to fall short of records by a few degrees along the coast, and several degrees for the NYC/NJ metro. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... Low level moisture increases tonight with a light SE flow. Models suggest stratus moving in with better chances of at least a broken deck occurring west of eastern LI and CT. This leads to a partly to mostly cloudy Monday. There appears to be enough isentropic and low level lift for a chance of a sprinkle in the afternoon as there`s significant subsidence above 800 hPa causing stratocu to spread. Highs will still range mostly 70-75. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... NWP remains on track with a deep upper level trough with strong meridional flow approaching the region Monday night as the jet dives into the Southeast. The question that remains is the timing of the very slow moving frontal passage. The GEFS has about 10 members that support the slower deterministic ECMWF timing. Thus, a good chance for rain to continue through Wednesday especially on Long Island and CT. Then, mainly dry weather is expected by Thursday night through next weekend. Winds are a potential issue Tuesday through Tuesday evening. There is a low level jet ahead of the cold front and the models have pretty good agreement with the 50-60 KT magnitude. Thinking of gusts of 35 to perhaps 45 KT. Have kept the TSTMs for Tue AFTN and Evening with potential for long narrow CAPE. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... VFR through at least 06z Mon as high pres gradually moves east through tonight. S/SE winds 8-12 kt develop later this morning and afternoon with seabreeze enhancement at coastal terminals. Aft 06z tonight, the second night of onshore flow, may start seeing indications of fog and/or stratus development, however the high may not be far enough offshore for MVFR/IFR CIGS. High clouds could also limit fog development. Would like to see more of the hi-res guidance later today before committing to IFR conds. .OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... .Mon...Morning MVFR/IFR possible in stratus/fog, then VFR. S/SE G20 kt Mon aftn. .Mon night-Tue...Potential a period of S/SE G30-40 KT with LLWS SSW 45-55kt@2kft for coastal terminals. MVFR/IFR developing in -RADZ Mon night, continuing with SHRA and low prob/sparse TSRA Tue. .Tue night-Wed...IFR possibly continues in SHRA Tue night, improving to MVFR Wed. .Wed night-Thu...VFR, with iso-sct MVFR in SHRA. && .MARINE... Quiet conds on all waters through Mon as high pressure over the area slowly shifts east. The pressure gradient will begin to tighten on Mon as low pressure strengthens over the Great Lakes. SCA conds are expected to develop Mon night with the potential for gale force gusts Tue into Tue night, all waters. The gale potential will depend on mixing over the waters, but should be able to mix down 35-40kt forecast at 1000mb, especially over the ocean. Winds just off the deck may be slightly weaker on the non- ocean waters and gales may only occur with any heavier showers/tstms. Winds will slowly diminish from W to E Tue night, and the progression of the front/LLJ will determine the end time for the SCA/gale hazards. May need to keep headlines up into Wed for the eastern waters. Seas on the ocean are forecast to remain above 5 ft through Thu, due to a SE swell from a good fetch around the departing high. This could be overdone however. && .HYDROLOGY... Expect nuisance urban ponding late Tuesday into Wednesday, especially across the NY Metro, Long Island and Southern CT. Storm total of 1.5 to 3" now expected, but flash and river flooding are not anticipated. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...Tongue NEAR TERM...Tongue SHORT TERM...Tongue LONG TERM...Tongue AVIATION...24 MARINE...24 HYDROLOGY...Tongue

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