Area Forecast Discussion
Issued by NWS Upton, NY

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079 FXUS61 KOKX 260153 AFDOKX Area Forecast Discussion National Weather Service New York NY 953 PM EDT Fri May 25 2018 .SYNOPSIS... High pressure remains off the southeastern coast into Saturday morning. A back door cold front moves through late Saturday afternoon into Saturday night, then becomes nearly stationary south of the waters through Memorial Day. Another cold front will move through from the north on Tuesday, followed by high pressure building in through the middle of next week. A storm system should then impact the region for the end of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Minor changes were made with this update to reflect the latest trends in observations and guidance. The forecast appears on track. The region remains on the NW periphery of the sub-tropical ridge overnight. Early Saturday morning, a northern shortwave moves out of the upper midwest, and an eastern Canada trough begins to dig into northern New England. This will only bring an increase in high clouds to mainly western zones late. An unseasonably mild airmass will remain in place overnight, with lows possibly not falling below the 70 degree mark in parts of NYC. There is a moderate risk for rip currents tonight at area Atlantic Beaches.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... During Saturday the flow will remain nearly zonal as the northern stream shortwave moves through the flow, and into the region by late Saturday afternoon. Meanwhile, the eastern trough and building high pressure over Hudson Bay will push a back door cold front into the region by late SAturday. The combination of the shortwave and cold front will bring a chance of showers and thunderstorms by late in the day. Mixed layer CAPE and surface instability increases and remains into Saturday evening, AS a warm and increasingly humid airmass remains, so will have thunder into the evening. Instability and CAPE quickly decrease toward 04Z and will have showers with a chance of thunder. Then by late Saturday night, with the cold front through the region will mention just showers. There is a moderate risk for the meteorological enhancement of rip current beaches at Atlantic Beaches from Saturday into Saturday evening. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Sunday remains a question mark at this time. Both the NAM and ECMWF allow high pressure over the Maritimes to erode precipitation chances from N to S through the day substantially. The GFS output indicates essentially a rainy day, at least through 2pm or so. Pops were unchanged, ranging from likely in the morning to chance in the afternoon. If the drying trend continues in the data however, these will be pulled back in subsequent forecasts. The high looks to produce dry weather on Monday. The guidance has trended up with temperatures as a result. A warmup on Tuesday as upper level ridging builds in, but a backdoor cold front comes through in the afternoon or evening. The GFS is the wet model yet again, but the weather has been kept dry until a model consensus builds. High pressure and dry weather on Wednesday, then a warm front and possible low pressure system for late Thursday and Friday. Chances for showers and thunderstorms have been included in the forecast. There could be a connection to Alberto moisture, so if this does occur, locally heavy rain will be possible. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... High pressure will move further offshore tonight into Saturday. A back door cold front approaches late Saturday and moves through Saturday night. Mainly VFR through the TAF period. SW winds 10-15 kt with lingering gusts 20-25 kt possible through around 02z. Winds gradually diminish thereafter and before increasing to around 10 kt on Saturday. There is a chance of thunderstorms late Saturday afternoon into Saturday evening, mainly from NYC terminals on north and west. Showers become more likely after 00z with possible MVFR. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: No unscheduled amendments expected. KLGA TAF Comments: Gusts will diminish through 02z. KEWR TAF Comments: Gusts will diminish through 02z. KTEB TAF Comments: No unscheduled amendments expected. KHPN TAF Comments: No unscheduled amendments expected. KISP TAF Comments: No unscheduled amendments expected. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday Night...Showers likely with a chance of thunderstorms. MVFR developing late. .Sunday...IFR in the morning, becoming MVFR in the afternoon. Showers likely through early afternoon. .Monday...MVFR possible. .Tuesday-Wednesday...VFR. && .MARINE...
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Minor changes were made with this update to reflect the latest trends in observations and guidance. The forecast appears on track. Sub-Small Craft Advisory (SCA) conditions are expected on all waters around Long Island overnight, with winds generally 10 kt or less on the non-ocean zones and 15 kt or less on the coastal ocean waters (with gusts up to around 20 kt). Saturday and Saturday night winds and seas will remain below small craft levels with a weak surface pressure gradient force. Winds are expected to remain below SCA levels Sunday-Wednesday. 5 ft seas are possible from Sunday into Monday on the ocean with NE flow.
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&& .HYDROLOGY... Dry through Saturday morning. From 3/4 to 1 inch of rainfall is likely from late Saturday afternoon through Sunday night. Heavy rainfall is a possibility Saturday night with locally higher amounts possible. Minor urban and poor drainage flooding will be possible Saturday night. No significant hydrologic impacts are anticipated Sunday- Thursday. There is a low potential for locally heavy rain from Thursday night through Friday. && .TIDES/COASTAL FLOODING... Water levels may be near minor flood thresholds along the south shore back bays of Nassau County and in western Long Island Sound with the Sunday afternoon and evening high tide cycle. Forcing for increased water levels will be increasing E-NE flow as a front stalls to the south and strong high pressure sets up E of New England, along with increasing astronomical high tides with the full moon on Tue the 29th. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...None. NJ...None. MARINE...None.
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&& $$ SYNOPSIS...Maloit/19/12 NEAR TERM...Maloit/19 SHORT TERM...19 LONG TERM...12 AVIATION...DS MARINE...Maloit/19/12 HYDROLOGY...19/12 TIDES/COASTAL FLOODING... EQUIPMENT...

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