Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 151728 AFDOKX Area Forecast Discussion National Weather Service New York NY 1228 PM EST Wed Nov 15 2017 .SYNOPSIS... High pressure today will be followed by a warm front passage tonight into Thursday morning. A cold front quickly follows Thursday afternoon as strengthening low pressure moves up the New England coast into Thursday night. High pressure builds into the region on Friday, before giving way to a low pressure system and cold frontal passage impacting the area over the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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High pressure remains in control today, centered across New England. Winds are beginning to veer to the east and southeast as the high slowly retreats to the NE. Moisture below the subsidence inversion will gradually increase and likely lead to expanding stratocumulus across at least Long Island but could build into portions of southeast Connecticut. Overall, a partly cloudy sky condition is forecast for the remainder of the afternoon with increasing middle and high level clouds late ahead of an approaching frontal system and upper trough to the west. Highs today will be around 5 degrees below normal, mainly in the mid to upper 40s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... A northern stream shortwave trough tracks across the northern Great Lakes tonight, with a shortwave embedded in it, helping to form a weak low off the Mid-Atlantic coast by Thursday morning. The combination of these too features should bring rain everywhere by late tonight. As the surface warm front lifts to the north, precipitation will become more convective in nature, so have gone with showers on Thursday. The showers will tapper off from W to E during the day is the axis of the northern stream shortwave trough passes to the east. Also, with the Showalter Index progged down to around 2 by late afternoon over the eastern 1/3 of the CWA, have introduced a slight chance of thunder there as well. Lows tonight should be around 5 degrees above normal (mid 30s- lower 40s, with mid 40s in NYC and its immediate surrounding area). Highs on Thursday should be near normal, from around 50 to the mid 50s across the region. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Low pressure and associated cold front moves east of the region Thursday night, with high pressure building in from the west. Gusty winds and cooler temperatures can be expected behind the front. Wind gusts to 30-35 mph will be possible Thursday night into Friday morning, especially across coastal locations. With high pressure building over the region Friday, expect dry conditions and winds gradually diminishing during the afternoon hours. The high quickly moves east of the area Friday night, with our next system on our doorstep Saturday morning. Once again there are timing differences among operational models, with 00z GFS continuing to be on the faster side of consensus, bringing showers into area Saturday morning as opposed to afternoon. This faster timing is not preferred since upper trough should deepen with time as it approaches area, resulting in slower onset of showers, with most of rain falling from Saturday afternoon into Sunday morning. Some light precipitation does remain possible well north and west of NYC early Saturday morning, where temperatures could remain below freezing. Will have a few hours of light snow or a wintry mix possible. With precipitation remaining fairly light during this period, and temperatures rising, not expecting any accumulating snow, however, if precipitation starts off an hour or two earlier than forecast, a light coating can not be ruled out. across portions of Orange county. It should be windy out ahead of and behind this system. For now, will forecast gusts into the 30-35 mph, however can not rule out some gusts to 40 mph. The front pushes east, Sunday late morning/early afternoon, with dry weather expected Monday and Tuesday as high pressure builds back over region. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
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High pressure over the area gradually gives way to an approaching frontal system over the Midwest. A warm front lifts through the area Thursday morning, quickly followed by a cold frontal passage. VFR to start the day with the development of MVFR ceilings late this afternoon into early this evening. Showers work into the area after midnight with a period of IFR likely Thursday morning. VFR returns by mid day. N-NE winds 5-10 kt this morning will veer E briefly before shifting SE during the afternoon. On Thursday, winds become W and increase to near 15 kt with some gusts to 25-30 kt likely by midday after the frontal passage. 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: Timing of MVFR conditions may vary by 1-2 hours. Timing of Winds gusts on Thursday may vary by 1-3 hours. KLGA TAF Comments: Timing of MVFR conditions may vary by 1-2 hours. Timing of Winds gusts on Thursday may vary by 1-3 hours. KEWR TAF Comments: Timing of MVFR conditions may vary by 1-2 hours. Timing of Winds gusts on Thursday may vary by 1-3 hours. KTEB TAF Comments: Timing of MVFR conditions may vary by 1-2 hours. Timing of Winds gusts on Thursday may vary by 1-3 hours. KHPN TAF Comments: Timing of MVFR conditions may vary by 1-2 hours. Timing of Winds gusts on Thursday may vary by 1-3 hours. KISP TAF Comments: Timing of MVFR conditions may vary by 1-2 hours. Timing of Winds gusts on Thursday may vary by 1-3 hours. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .18z Thursday...MVFR or lower in showers, mainly in the morning. W-NW winds G20-30KT possible in the afternoon. .Thursday night-Friday...VFR. NW winds G25-30KT, strongest Thursday night. .Saturday...Sub VFR conditions possible by the afternoon and becoming likely towards evening. S-SW winds G25-35KT. .Sunday...Conditions improve to VFR. NW winds G25-30KT. .Monday...VFR. NW winds 20-25KT.
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&& .MARINE...
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A light to moderate pressure gradient will limit winds below SCA levels through Thursday morning. The pressure gradient tightens Thursday afternoon, with winds up to 25 KT and gusts up to 30 kt. Seas remain below Small Craft Advisory (SCA) levels on all waters through tonight. SCA seas develop on the coastal ocean waters Thursday morning. As a result have issued an SCA for the coastal ocean waters from 11z- 23z Thursday and on the non-ocean zones from 17z-23z Thursday. Gusty winds behind a cold frontal passage Thursday night into Friday should produce gale force gusts on most if not all of the area waters. As a result, a Gale watch has been issued for all the waters for Thursday night through noon on Friday. Its possible gales on the non-ocean waters fall below 35kt before noon on Friday. Winds diminish Friday afternoon and overnight. Another strong cold front affects waters Saturday into Sunday. Once again, the potential exists for gale force gusts both ahead of, and behind front Saturday afternoon into Sunday, especially on ocean waters south of Long Island. Gale potential will continue to be highlighted in the Hazardous Weather Outlook (HWO).
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&& .HYDROLOGY... Dry through this evening. Less than 3/4 of an inch of rain is expected from late tonight into Thursday evening. As a result, no significant hydrologic impacts are expected. There is the potential for another rainfall event late Saturday into Sunday, with locally heavy rainfall possible. At this time, it is too early to specify amounts or what the exact impacts, if any, will be. && .TIDES/COASTAL FLOODING... Persistent, strengthening SE flow Tonight and Thursday will bring water levels in the South Shore Back Bays of NYC/Nassau and Western Suffolk County to near Minor Coastal Flood Thresholds. There is some potential for widespread minor coastal flooding during the Thursday morning high tide in this area, depending on the exact orientation and strength of the SE flow. The high tide Thursday afternoon is the lower of the two high tides, this coupled with winds shifting to the W to NW should limit any coastal flood threat to just Thursday morning`s high tides. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Gale Watch from Thursday evening through Friday morning for ANZ330-335-338-340-345-350-353-355. Small Craft Advisory from noon to 6 PM EST Thursday for ANZ330- 335-338-340-345. Small Craft Advisory from 6 AM to 6 PM EST Thursday for ANZ350- 353-355. && $$ SYNOPSIS...BC/DS NEAR TERM...Maloit/DS SHORT TERM...Maloit LONG TERM...BC AVIATION...IRD MARINE...BC/Maloit HYDROLOGY...BC/Maloit TIDES/COASTAL FLOODING...

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