Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 290010 AFDOKX Area Forecast Discussion National Weather Service New York NY 810 PM EDT Sun May 28 2023 .SYNOPSIS... High pressure remains into tonight, weakening late. A backdoor cold front moves through Memorial Day. High pressure then dominates through the upcoming week, with weakening southern low pressure tracking south of the region. A cold front approaches Friday and passes though late in the day or at night. Canadian high pressure builds back into the region for next weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... The forecast is mainly on track with minor adjustments made to some of the hourly weather elements based on the latest trends. The upper Omega block will remain in place through tonight while surface high pressure gradually weakens. The high will keep higher clouds associated with low pressure along the southeastern coast suppressed, moving into the southern areas. As the high weakens late a backdoor cold front will begin to approach. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/... The upper ridge will remains over the northeast and mid Atlantic into Tuesday as the upper low along the southeastern coast slowly weakens. Meanwhile the timing of the backdoor cold front is a little quicker, moving into the eastern areas mid morning Monday, and move across the region into the afternoon, as east flow develops, bringing in a cooler airmass. By evening the front will be moving into eastern Pennsylvania. High pressure then returns Monday night into Tuesday. Only a few high clouds will accompany the frontal passage as there is little moisture through the atmosphere column. The low along the southeastern coast moves inland and weakens Monday, and then drifts east under weak steering flow. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Surface high pressure ridge will stretch across the area to start the long term, and models continue to show low pressure meandering off the Mid Atlantic Coast as it weakens. Most of the guidance continues to keep rain out of the forecast area with the northern periphery maybe brushing the offshore waters at times Tuesday night through Wednesday. Will continue with a dry forecast for this period over land, with highs on Wednesday generally in the 70s. High pressure remains in place for Thursday with temperatures warming through the boundary layer. Models are now averaging around 15C at 850mb, which has trended cooler over the past couple of days, and mixing might not be as deep as 850mb with a easterly flow, although it will be a light flow. Thought deterministic NBM could be too cool, so blended in the warmer 50th percentile. Still some uncertainty regarding when a cold front will be passing through during the Friday/Friday night time frame, but the timing has trended slower over the past couple of days. Have gone with a slight chance of a shower/thunderstorm north of the city in the afternoon, then as slight chance everywhere at night. A prefrontal trough may promote an offshore flow for some coastal areas, and with 850mb temps progged at 16-18C, have gone close to the 50th percentile NBM, which was warmer than deterministic. Cooler for the weekend with high pressure building in from the north or northeast behind the cold front. A cyclonic flow aloft will bring a slight chance of an afternoon shower NW of the city Saturday afternoon, otherwise dry through the weekend. NBM looked too warm for high temperatures considering an onshore flow and progged temps at the top of the mixed layer, so used the 25th percentile. Similar temperatures are expected for Sunday - mostly in the 70s. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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Gradually weakening high pressure across the area will give way to an approaching cold front from the north early Monday. High pressure from the north returns thereafter. VFR conditions are expected through the TAF period. Light southerly winds tonight will become nearly calm and variable direction overnight. Winds will transition to more easterly flow on Monday and become gusty going into Monday afternoon. Wind speeds generally below 10 kt tonight into Monday morning, and near 10-15 kt Monday afternoon with gusts near 20 kt. However, east of NYC terminals Monday afternoon, winds are forecast to be more near 15 kt with gusts around 25 kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of gusts on Monday could be 1-3 hours off with start and end times. Gusts could occasionally be a few kts higher than in TAF. OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY... Monday night: VFR. Easterly winds near 10-15 kt with gusts near 20 kt for evening, diminishing overnight. Tuesday through Thursday: VFR. Friday: Mainly VFR. Possible showers/thunderstorms and MVFR, mainly at night. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/
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&& .MARINE... Cold water headlines continue through tonight. High pressure over the waters weakens late tonight as a backdoor cold front approaches. Winds and seas will remain below advisory levels across all the waters. The backdoor cold front moves across the water Monday morning into Monday afternoon. High pressure then builds in behind the front. Winds will be increasing behind the front with gusts approaching 25 kt on the ocean waters, south shore bays, and New York harbor in the morning and into the afternoon, east to west. A SCA has been issued for these waters. Ocean seas may still be at 5 feet into Tuesday morning on the eastern ocean and into the afternoon on the western ocean waters, and the advisory may need to be extended. On the eastern bays and the far eastern Long Island Sound gusts will be just under 25 kt and will mention occasional gusts to 25 kt. However, if later forecasts indicate higher wind gust potential an advisory may be issued for these waters. And on the central and western Long Island Sound gusts are expected to remain below 25 kt. With high pressure over the waters once advisory conditions end sub SCA conditions will continue through the end of the week. Persistent SE swells gradually subside middle to late week. && .HYDROLOGY... No hydrologic impacts are expected through the entire forecast period. && .TIDES/COASTAL FLOODING... A moderate risk of rip current development at Atlantic Ocean beaches continues through Tuesday. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from noon to 8 PM EDT Monday for ANZ338- 345. Small Craft Advisory from 10 AM Monday to 6 AM EDT Tuesday for ANZ350. Small Craft Advisory from noon Monday to 6 AM EDT Tuesday for ANZ353-355. && $$ SYNOPSIS...JC/MET NEAR TERM...MET SHORT TERM...MET LONG TERM...JC AVIATION...JM MARINE...JC/MET HYDROLOGY...JC/MET TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.