Area Forecast Discussion
Issued by NWS Upton, NY

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438 FXUS61 KOKX 241932 AFDOKX Area Forecast Discussion National Weather Service New York NY 332 PM EDT Tue Sep 24 2024 .SYNOPSIS...
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High pressure weakens over the region through Wednesday as a frontal system approaches from the west. Its associated warm front lifts though the region Wednesday night into early Thursday, followed by a cold front Thursday night. High pressure builds to the north Friday and then remains into the beginning of next week.
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&& .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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Mostly cloudy for tonight with a low level easterly flow combined with increasing moisture in the mid levels ahead of an approaching weak system to our west. It will be dry for the most part, but a few showers may sneak into the western zones late tonight. NBM was used for low temperatures, but adjusted upward a little over parts of Long Island with the anticipation of a mostly cloudy sky and persistent easterly flow.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
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Cloudy through the period with rain chances generally trending upward slowly across the area. The better chances will be during Wednesday night with a warm front passing through, and the probabilities will be highest north and west of the city. Models showing some elevated instability, but will leave out the mention of thunder as shortwave lift doesn`t look particularly strong, and mid level lapse rates will be unfavorable with a longwave ridge aloft still nearby. Cloudy otherwise through the short term forecast. Blended NBM 25th and 50th percentiles for high temps due to the cloud cover. Highs only in the 60s for most areas.
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&& .LONG TERM /THURSDAY THROUGH TUESDAY/...
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A northern stream upper trough closes off and moves across the upper midwest and southern Canada into northern New England Thursday into Thursday night. An associated frontal system, first a warm front Thursday morning, then a cold front late Thursday into Thursday night, moves across the region and brings chances of precipitation. The best chances will be across the northern tier. There will be some surface based CAPE and instability, along with some shear, for a chance of thunderstorms late Thursday into Thursday night. Precipitation may linger just to the south and west of the region Friday into Saturday evening until an upper ridge builds eastward. The high amplitude ridge builds between the northern offshore closed low and another closed low that remains nearly stationary over the lower Mississippi Valley Saturday and Sunday. This ridge and associated high pressure to the north will bring a period of dry weather Saturday night through Monday. The upper ridge weakens early next week and the southern closed low begins to move northward and may bring chances of precipitation back into the region for Tuesday. Temperatures will be a few degrees above normal Thursday and Friday, and then near seasonal normals Saturday into the beginning of next week.
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&& .AVIATION /19Z TUESDAY THROUGH SUNDAY/...
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High pressure remains in control through today. A frontal system approaches tomorrow. Mainly VFR expected today though low stratus could lead to temporary MVFR conditions occasionally. While things have scattered out for now from this morning, its still worth keeping an eye on. More widespread MVFR ceilings are expected to move into most terminals after 00-03Z tonight. MVFR will hold all tomorrow. There is a possibility for IFR starting tomorrow morning at city terminals and terminals north and west, but too low confidence to include in the TAFs. Spotty/sparse coverage of SHRA may approach the terminals from the west on Wednesday, but confidence is too low to include in the TAFs at this time. It may be too dry for SHRA to develop or become impactful. E-NE winds around 10 kt today. An occasional gust of 15 to 20 kt is possible into the early evening hours. Winds will drop below 10 kt tonight, then increase tomorrow 10-15 kts with gusts peaking near 20 kts. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Unscheduled amendments possible for changing flight categories due to marginal MVFR cigs. OUTLOOK FOR 21Z WEDNESDAY THROUGH SUNDAY... Wednesday night: Chance of showers with MVFR or lower cond throughout, but mainly after midnight at KISP/KGON. Slight chance of a tstm in the evening from the NYC metros north/west. Thursday: Chance of mainly morning showers/MVFR cond, otherwise VFR. Friday - Sunday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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&& .MARINE...
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Long period easterly swells from a slowly departing offshore low will to continue to produce advisory level seas on the ocean through Wednesday night with waves possibly remaining near 5 feet through Thursday evening as swells diminish. SCA has been extended through Wednesday night for the time being. For Thursday night, ocean seas likely fall below 5 feet as the swells continue to diminish and as a northerly flow develops behind a frontal system. Sub advisory levels will then continue through the weekend. For the non ocean waters winds and seas will remain below advisory levels Thursday through the weekend.
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&& .HYDROLOGY...
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There are no hydrologic concerns through early next week.
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&& .TIDES/COASTAL FLOODING...
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Water levels continue to slowly recede as high tides lower. However, easterly swells have made it difficult for back bay locations of western LI to drain. On-going brief minor coastal flooding at the most vulnerable locations in the south shore back bays this afternoon, will be ending by early this evening. Additional coastal flooding is not anticipated beyond this high time cycle. The high risk of rip currents continues through Wednesday evening at all the ocean beaches, and through Thursday evening at the Suffolk County beaches. There is a moderate risk Thursday at the New York City and Nassau ocean beaches. Offshore low pressure southeast of Long Island was still producing long period E/SE swells across the waters. These swells will be lowering late Thursday and continue lowering Thursday night and Friday.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...High Risk for Rip Currents through Wednesday afternoon for NYZ075- 080-081-178-179. NJ...None. MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ350-353- 355.
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&& $$ SYNOPSIS...JC/MET NEAR TERM...JC SHORT TERM...JC LONG TERM...MET AVIATION...BR/MW MARINE...JC/MET HYDROLOGY...JC/MET TIDES/COASTAL FLOODING...