Area Forecast Discussion
Issued by NWS Upton, NY

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006 FXUS61 KOKX 120759 AFDOKX Area Forecast Discussion National Weather Service New York NY 359 AM EDT Sun May 12 2024 .SYNOPSIS...
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A frontal system approaches this morning and passes south and east of the area later today. High pressure returns Sunday night. A warm front passes north of the area Monday. High pressure moves offshore Tuesday with low pressure approaching from the west. An area of low pressure passes south of the area Wednesday and then southeast of the area Wednesday night into Thursday. Weak high pressure then follows going into Friday before another low approaches for the start of next weekend.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A weak frontal system is approaching the area this morning with a midlevel shortwave and passing through late morning into early afternoon. Light showers have already developed along an occluded front in western portions of the CWA and will weaken before dissipating as they track east. Areas around the NYC metro and west and south of the NYC metro could see totals around or just below 0.25" with amounts quickly tapering east and north of the NYC metro. Even though lift along the occluded front will be weak, we will still see increased moisture and positive vorticity advection associated with the midlevel shortwave. The east end and east CT may see no rain at all today. The atmosphere will be mostly stable, so no thunderstorms are expected, however, a few isolated showers are possible in S CT and LI this afternoon, based on the latest CAMs. High pressure tries to build in the wake of the weakened exiting low this afternoon, so subsidence will really be working against the development of these afternoon showers, but may be aided by lingering midlevel moisture and energy associated with the exiting shortwave. A fairly deep shortwave trough passing over today will limit highs to the mid-50s, which is about 10-15 degrees below seasonal averages.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
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Heights will rise Sunday night as the upper trough continues departing to the east. Surface high pressure will be in place leading to mostly dry conditions. Clouds should slowly diminish through the night with mostly clear to partly cloudy skies by early Monday morning. Another chilly night is expected with lows in the 40s. A ridge will continue to build on Monday leading to noticeably warmer weather compared to Sunday with highs in the low/mid-60s to the east with onshore flow and western inland areas in the upper-60s to low-70s. A warm front will also be skirting the area to the north, extending from a low in Canada. This warm front could lead to a few showers that dissipate as they track north to south. Confidence in the showers occurring, though, is low due to the riding aloft and surface high pressure working against them. PWATs around 1-1.2" will be in place, though.
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&& .LONG TERM /TUESDAY THROUGH SATURDAY/...
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In the mid levels, the local area appears to be in between a trough and a ridge. The trough is over SE Canada and the ridge is southeast of the area, based in the Atlantic. The ridge moves farther east Tuesday night into Wednesday with a trough moving in. The center of the trough moves across either Wednesday night or Thursday. There are differences resolving this feature. For Thursday night through Friday night, the local area is shown to be in between troughs in the mid levels, with some brief ridging. Next trough moves in for the start of next weekend. At the surface, a warm front moves farther north of the area Tuesday with low pressure developing along a cold front to the west. There are multiple areas of low pressure developing along this front. Eventually, there is one main low that is forecast to move south of Long Island Wednesday and then farther out into the Atlantic Wednesday night into Thursday. There are model differences in their depiction of the low and its translational speed. Chances for rain showers increase Tuesday, with rain showers expected to be widespread across the area by Tuesday night and continuing into Wednesday. Chances for rain showers remain for Wednesday night with a slight chance of rain showers Thursday. Rain could be moderate to possibly heavy at times Tuesday night into Wednesday. With colder air aloft and some elevated instability potentially, there could be a few embedded thunderstorms. Just left the thunderstorms as slight chance in terms of their probability. By Thursday night and Friday, high pressure starts to build in from the north and east, which will maintain mainly dry conditions through much of Friday night. The next low provides the next chances for rain starting out next weekend. Temperatures in the daytime look to average above normal Tuesday, below normal Wednesday, close to normal Thursday and Friday, and below normal next Saturday.
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&& .AVIATION /08Z SUNDAY THROUGH THURSDAY/... A weakening frontal system moves in going into today. Weak high pressure return later today and tonight. Some light rain showers are expected with this frontal system with higher chances for NYC terminals, KHPN and KSWF and lesser chances for KISP and KBDR. KGON may not receive any rainfall. Chances are too low for rain for KGON to include in their TAF. VFR is expected to transition to MVFR going into this morning. Some MVFR may last into this afternoon, but otherwise mainly VFR conditions are expected this afternoon into tonight. Wind speeds less than 10 kt expected during the TAF period. Wind direction overall southerly on average becoming more SW late in the TAF period. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... MVFR timing could vary from TAF by a few hours. Some fluctuation between VFR and MVFR possible going into this morning. OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY... Late Sunday night through Monday: VFR. Tuesday: MVFR or lower possible in mainly afternoon showers, an isolated thunderstorm possible inland. S winds 15kt coastal terminals. Tuesday night: MVFR likely in showers and possible tstms. S winds 10-15kt coastal terminals. Wednesday: MVFR or lower still likely in showers and t-storms. SE winds 10-15G20kt, becoming NE late day and at night. Wednesday night: VFR. N winds 10-15G20kt. Thursday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE...
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Winds are expected to remain below SCA conditions for the entirety of Sunday. Monday evening/early night may briefly reach 5 feet before dropping back down to 4 feet. Long term marine, initially below SCA conditions expected Tuesday into Tuesday night. Then, SCA conditions become probable Wednesday night into Thursday, especially on the ocean.
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&& .HYDROLOGY... No hydrologic impacts expected through next week. && .TIDES/COASTAL FLOODING...
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No coastal flooding is anticipated as astronomical tide levels continue subsiding into early next week.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JM/BR NEAR TERM...BR SHORT TERM...BR LONG TERM...JM AVIATION...JM MARINE...JM/BR HYDROLOGY...JM/BR TIDES/COASTAL FLOODING...