Area Forecast Discussion
Issued by NWS Upton, NY

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284 FXUS61 KOKX 231516 AFDOKX Area Forecast Discussion National Weather Service New York NY 1116 AM EDT Mon Sep 23 2024 .SYNOPSIS... High pressure near Maine will continue to nose southward through Tuesday. A frontal system then approaches on Wednesday and moves across on Thursday. High pressure slowly returns Friday and Saturday. && .NEAR TERM /THROUGH TONIGHT/...
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Nudged up PoPs just a bit to chance (25-30%) over the western half of the region this afternoon. A few sprinkles or showers associated with a weakening shortwave across Pennsylvania and Upstate NY may be able to work into NE NJ, the LoHud Valley, and the NYC metro before ridging and dry air in place helps to dissipate this activity. Any rain that does make it to the ground should be rather spotty and light. Otherwise, forecast remains on track and previous discussion follows. Upper trough and associated offshore low will continue pushing further east over the western Atlantic through tonight. Upper ridge axis overhead to start the day flattens as a weak shortwave approaches. The shortwave likely washes out this afternoon and evening with ridging taking over by tonight. High pressure near Maine will continue to ridge down through the northeast. The aforementioned shortwave should lead to partly sunny/mostly cloudy conditions through much of the day. The latest high resolution models are simulating some weak radar returns ahead of the weakening shortwave, which reach the western half of the area late this morning into the afternoon/early evening. The surface ridging from the high pressure and dry subcloud layer will likely limit how much reaches the ground. High temperatures will be slightly below normal in the upper 60s and lower 70s. Mostly cloudy conditions likely continue tonight as there will moisture in the low to mid levels moving around the periphery of the building ridge aloft. Lows look to fall into the lower 50s inland and middle to upper 50s closer to the coast.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... Ridging will remain along the eastern seaboard on Tuesday as a much more organized upper trough amplifies across the central states. This pattern will continue to bring varying levels of clouds during the day, but there should be some sunshine at times. Highs on Tuesday continue slightly below normal in the upper 60s and low 70s. The upper ridge axis starts sliding east Tuesday night into Wednesday. The surface ridging may weaken a bit, but still remain nearby across the New England coast. The upper trough is progged to split as the northern stream rushes out ahead of the southern stream. This should effectively prevent a deeper moisture feed up into the northeast. The northern stream shortwave sends a frontal system towards the area on Wednesday, with chances for showers slowly increasing through the day. Have capped PoPs at chance with the higher probabilities from the NYC metro on northwest. The lingering surface ridging prevent much progress into CT and Long Island, at least into the early evening. High temperatures continue slightly below normal in the upper 60s and low 70s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
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Key Points: * Showers continue mid week with a passing frontal system. * Greater likelihood of dry weather from Fri into the weekend. No significant changes in the long term period and stuck close to the previous forecast/NBM. A frontal system will move across the region during the start of the long term period, mainly Wednesday night through Thursday night. Expect at least some chance PoP for the entire region during this period. By Thu, a complex pattern will have taken shape over North America, with an omega block developing as upper ridging gets pinched off over the upper Great Lakes region, one closed low moves across Eastern Canada into the western Atlantic, and another closed low remains nearly stationary over the Plains and the Mississippi Valley. The low moving across Canada should send a back door front down through on Fri, with sfc ridging once again nosing down from eastern Canada from that point on into the weekend. High temperatures in the long term will remain in the 70s each day.
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&& .AVIATION /15Z MONDAY THROUGH FRIDAY/...
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High pressure remains in control today. Mainly VFR cond, but some BKN035 cigs may be around this morning til daytime heating helps lift/scatter these lower clouds. Cigs should lower back to MVFR late tonight into early Tue morning around 12Z Tue, and some BKN035 cigs could be around earlier than that. NE winds around 10kt. Some coastal terminals will however likely veer E-ESE this afternoon. Can`t rule out brief G15-20kt at the coastal terminals as well. Tonight, winds go back to the NE 10 kt or less. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... A brief gust 150-20 kt not out of the question this afternoon. Timing of MVFR cigs late in the TAF period may require later AMD. OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... Tuesday: MVFR likely in the morning, then VFR in the afternoon. NE-E winds occasional gusting 15-20kt. Wednesday: Chance of showers with MVFR possible. E winds G15-20kt into the evening. Thursday: Chance of showers, mainly early, with MVFR possible. Friday: 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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Elevated long period swells from slow departing offshore low pressure will continue for several days. A Small Craft Advisory remains in effect on the ocean waters and has been extended through Tuesday Night. This may need to be extended into Wednesday even though seas should begin subsiding Tuesday night into Wednesday. Winds are expected to remain below SCA levels through Wednesday. An extended period of hazardous 5+ foot seas should continue into at least Wednesday night. Seas may either subside below 5 ft by Thursday, or at least be confined closer to the offshore waters.
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&& .HYDROLOGY... There are no hydrologic concerns through next weekend. && .TIDES/COASTAL FLOODING...
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Minor coastal flooding continue with high tide this afternoon, but impacts and areal coverage will be less than previous days. The offshore low responsible for the easterly swell that has helped pile water into the area will work slowly southeast through early this week. The combination of these two factors will bring an end to the widespread coastal flooding after high tide this afternoon. No changes were made to the ongoing headlines currently in place through this afternoon The most vulnerable locations in the south shore back bays, particularly in southern Nassau, may see brief minor coastal flooding with high tide Tuesday afternoon. The back bays can be slow to drain which has occurred in similar past events, so have gone closer to Stevens guidance for locations such as East Rockaway, Reynolds Channel, and Freeport. A coastal flood statement may eventually be needed for these locations Tuesday afternoon. No additional issues anticipated beyond that time. The high risk of rip currents continues through Tue evening with offshore low pressure still bringing long period E-SE swells.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Coastal Flood Advisory from 2 PM this afternoon to 6 PM EDT this evening for CTZ009. NY...Coastal Flood Advisory from 2 PM this afternoon to 6 PM EDT this evening for NYZ071. Coastal Flood Advisory until 3 PM EDT this afternoon for NYZ074-075-178-179. High Risk for Rip Currents through Tuesday afternoon for NYZ075-080- 081-178-179. NJ...Coastal Flood Advisory until 3 PM EDT this afternoon for NJZ006-106-108. MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ350-353- 355.
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&& $$ SYNOPSIS...BC/DS NEAR TERM...DR/DS SHORT TERM...DS LONG TERM...BC AVIATION...BC/BG MARINE...BC/DS HYDROLOGY...BC/DS TIDES/COASTAL FLOODING...