Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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281 FXUS61 KOKX 010534 AFDOKX Area Forecast Discussion National Weather Service New York NY 134 AM EDT Wed May 1 2024 .SYNOPSIS... Weak low pressure and a frontal boundary shift farther offshore through Wednesday. High pressure will then take control of the weather from Wednesday afternoon into at least Friday. A weakening frontal system will approaches for the second half of the weekend, followed by high pressure building toward Monday. A warm front will approach late Tuesday and Tuesday night. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Tstms made it into NYC and points north/west as well into parts of S CT this evening. One weakening cell was near HVN as of 03Z, with a stronger cell over nrn Middlesex CT. Showers still linger in their wake back into ern PA, so previous chance PoP forecast for the overnight still stands. Meanwhile, moisture trapped under a low level inversion will keep us cloudy overnight. Low temperatures should be close to normal, in the upper 40s/lower 50s. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... Cloudy with a low chance of lingering showers to start the day Wednesday. Expecting the threat of showers to end by noon as high pressure slowly builds in. Anticipating partial sunshine for the afternoon, but there`s low confidence in the cloud cover forecast during this time. Some guidance even suggests a chance of afternoon showers in spots with lingering moisture and weak shortwave lift. The cloud uncertainty has implications on the high temperature forecast as well. Would be more inclined to go with NBM 50th percentile if there was higher confidence in a mostly sunny afternoon. Hedged by going with an even blend of 50th percentile and the cooler deterministic NBM (which was closer to the 25th percentile). High temperatures will be above normal, especially west of the Hudson River, where highs are expected to be in the mid 70s. Dry weather for Wednesday night with weak high pressure in control. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... There remains a fair amount of uncertainty in the long term. A repeating question throughout the period will be how long mid and upper level ridging can hold as disturbances from the west will attempt to break down any ridging that is in place from time to time. On Thursday modest ridging works into the area as thicknesses climb some. Clouds likely linger through a good portion of the morning with an inversion down low in the profile which may prevent mixing initially. Towards afternoon expect more mixing with partial sunshine with 850 mb temps getting at or just above 10 C expect temperatures to get above normal, and potentially well above normal further inland away from the coast. Interior locations will have a chance of reaching the lower 80s. Went above NBM deterministic as probabilities point to a warmer day. It should remain primarily dry with only a minimal / slight shower chance across northeastern zones. Thursday night the winds will shift to the NE as high pressure begins to nudge down from the north across Eastern Canada and the frontal boundary is sent further south into Friday. A cooler day across the region takes place Friday with a NE to E onshore wind bringing temperatures closer to normal. It may take awhile for the cooler ocean air to entrain further inland so went above the NBM with regard to temps, especially further west. The progression of the next disturbance during the weekend continues to slow. Have kept all of Saturday dry despite plenty of mid and upper level cloud cover. The upper level ridge axis doesn`t pass until Saturday evening. Primarily have kept Saturday dry and introduce low end PoPs for the afternoon and evening, and further west. Have the high end chance PoPs coming in towards daybreak Sunday and continue through the day for the most part. Stuck fairly close to NBM PoPs with just a few manual tweaks. The frontal boundary will weaken as it slams into the ridge in place, thus precip amounts are expected to be light. Amounts at this time look to be on the order of a half inch or less. There appears to be good model agreement that the cold frontal boundary falls apart as it moves through late Sunday night into early Monday. The mid levels should dry out and bring precip to an end, however the question remains as to how quickly the low levels will dry out for the day Monday. This will greatly impact the temperatures forecast for Monday. The global guidance suggests enough ridging works in to provide enough drying and mixing and a return to some sun resulting in seasonably warm temperatures as 850 mb temps warm again into early next week. A warm front will then attempt to approach from the west and possibly lift north later Tuesday of next week. There remains uncertainty as to whether the warm front will remain nearby or lift to the north late Tuesday and will thus affect temperatures across the area. Mid level energy from the west will attempt to break down any riding in the mid levels. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... A wave of low pressure along a stationary front south and west of the area will pass to the south and east of Long Island tonight. Weak high pressure will follow for Wednesday. Tstms that impacted any terminals have weakened and are passing east. Scattered showers and mainly MVFR cigs expected for the overnight into the morning hours for most of the NYC metro terminals, with IFR for KLGA. Mainly IFR cigs expected for the terminals to the north/east across the lower Hudson Valley and across Long Island/S CT, with improvement to MVFR then VFR during the morning hours. MVFR cigs should take longer to improve at the Long Island and S CT terminals. NE winds mostly 10 kt or less (strongest at KLGA) should back more to the N overnight. Late morning/afternoon S-SE sea breezes expected at all the terminals but KSWF. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... AMD possible for fluctuating cigs overnight into Wed morning. Low confidence in MVFR at KJFK, KEWR and KTEB. Cigs may be mostly VFR tonight or become VFR earlier Wed morning than TAF timing. OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... Wednesday night: MVFR cigs possible. Thursday through Friday: VFR. Saturday: Mainly VFR. Chance of showers and MVFR cond in the afternoon and at night. Sunday...Chance of MVFR or lower in showers. ESE winds G15-20kt. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... A weak pressure gradient remains in place, with an extended period of sub advisory conditions. Ocean seas won`t start to climb above 2 or 3 feet until late Sunday and Sunday night when marginal SCA conditions may develop ahead of an approaching front. && .HYDROLOGY... There are no hydrologic concerns attm. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JC/JE NEAR TERM...JC/JE/BG SHORT TERM...JC LONG TERM...JE AVIATION...JT MARINE...JC/JE HYDROLOGY...JC/JE