Area Forecast Discussion
Issued by NWS Upton, NY

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203 FXUS61 KOKX 211733 AFDOKX Area Forecast Discussion National Weather Service New York NY 133 PM EDT Tue May 21 2024 .SYNOPSIS... High pressure will be in control through Wednesday night, then give way to an approaching cold front on Thursday. The front will move across Thursday night and stall to the south as waves of low pressure track along it. Another cold front will move across on Saturday, followed by another frontal system early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... The forecast is on track with only minor changes needed to trend from earlier obs. Fog on Long Island Sound had expanded along the CT coast west to Bridgeport and is now in process of burning off. High pressure slowly pushes off the East Coast today, but remains over the area enough to keep the area dry. An upper level ridge pushes east, but flattens as an upper level shortwave over the Great Lakes region moves east, passing well north of the area. With mostly sunny skies expected for this afternoon, today will be a warm day, especially for the interior, where a southwesterly flow advects a warm and increasingly more humid air mass today. Continued the trend of blending the 50th percentile with the deterministic NBM, which gives high temperatures in the middle 80s for northeast New Jersey and the Lower Hudson Valley. Elsewhere, temperatures in the 70s to near 80 can be expected, with the immediate shore seeing upper 60s for highs thanks to onshore flow and relatively cooler ocean temperatures. Dew points will rise into the upper 50s to middle 60s. Lows tonight will only drop to the 60s across New York City, northeast New Jersey, and the Lower Hudson Valley. Elsewhere, lows in the 50s can be expected. There may be another round of stratus and fog, moving in from the east. However, confidence was not high enough to include in the forecast, but some guidance is pointing to this scenario once again. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... The high slowly moves east on Wednesday allowing a pre-frontal trough to approach during the day. However, much, if not all the area, will remain dry. There is just a slight chance for showers and thunderstorms for the extreme western portion of Orange County on Wednesday. Continued well above normal temperatures for Wednesday and Thursday, with highs in the middle to upper 80s away from the coast (approaching 90 for northeast New Jersey). The coast will see temperatures range from the upper 60s to lower 80s for highs on Wednesday, and a couple of degrees warmer on Thursday. High pressure will eventually give way to an approaching cold front Wednesday night into Thursday. The parent low attached to this front will be weakening as it moves farther north of the Great Lakes leading to a weakening of the cold front. There will be a chance for showers and thunderstorms out ahead and along the cold front for Thursday into Thursday night. The cold front is forecast to move across Thursday night. Chances for showers and thunderstorms decrease late Thursday night after the cold frontal passage. There is potential for some thunderstorms to be strong to severe with the cold front with forecast surface CAPE values of 1000-2000 J/kg and forecast 0-6 km AGL bulk shear of 30 to 35 kt. Right now, coverage is expected to be isolated to scattered of, mainly for points north and west of New York City. No hydrologic concerns at this time as showers and thunderstorms will be fast moving, really limiting total rainfall accumulations. The Storm Prediction Center has placed the entire area in a marginal risk for severe thunderstorms, && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... There is currently a lot of uncertainty through the extended period with timing of a cold frontal passage Thursday night, and where this front will eventually stall. Waves of low pressure are expected to track along the stationary front which may bring a chance pf precipitation, showers, and potentially thunderstorms, to the area. Near upper level zonal flow will bring a more amplified trough north of the Great Lakes and into southeastern Canada Saturday into Saturday night, with another cold front approaching the region before weakening. Then for early next week an even more amplified trough will pass through the Great Lakes and northeast bringing a surface low across the region. While there are chances for precipitation during most of the extended period there will also be periods of dry weather. With the uncertainties have followed the NBM probabilities. Otherwise, a warm airmass will remain across the region with temperatures above normal Thursday night into the beginning of next week. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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Weak surface high pressure remains in control through Wednesday. VFR with southerly winds increasing to around 10-12KT with sea breeze enhancement. Southerly flow weakens and continues overnight, with a chance of MVFR to IFR stratus developing late tonight at KISP, KBDR, and KGON. VFR expected on Wednesday, with southerly flow increasing to about 10-12KT again. NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... No unscheduled amendments expected. Winds at KJFK may be as high as 15kt with sea breeze enhancement. OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... Wednesday Afternoon: VFR. Wednesday Night: IFR is possible late, mainly east of the NYC terminals. Thursday: VFR in the morning, then becoming MVFR with showers and thunderstorms likely during the afternoon. Friday: VFR. Saturday and Sunday: Generally VFR. A chance of showers with MVFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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&& .MARINE... Marine dense fog advisory was cancelled for Peconic/Gardiners Bays and continues til 11 AM for the ern Sound and ocean waters. There may be another round of fog tonight, but not enough confidence to mention fog on the waters at this time. Otherwise, sub-SCA conditions expected on all waters through Thursday. However, this afternoon and Wednesday afternoon are likely to see a southerly coastal jet produce gusts up to 20 kt late today and 20-25 kt on Wed, and seas of 3-4 ft in the NY Bight, possibly touching 5 ft. Winds and seas will be below SCA levels across the waters Thursday night through Saturday night. && .HYDROLOGY... No hydrologic impacts expected through the forecast period. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...None. NJ...None. MARINE...None.
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&& $$ SYNOPSIS...BG/JP NEAR TERM...BG/JP SHORT TERM...JP LONG TERM...MET AVIATION...JT MARINE...BG/JP/MET HYDROLOGY...JP/MET