Area Forecast Discussion
Issued by NWS Upton, NY

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001 FXUS61 KOKX 161550 AFDOKX Area Forecast Discussion National Weather Service New York NY 1050 AM EST Tue Jan 16 2018 .SYNOPSIS... High pressure continues to move offshore today, allowing low pressure to approach from the west, passing just north of the area tonight. Meanwhile, a developing coastal low will develop and pass just east of Montauk during the day Wednesday, then moves up the coast into the Canadian Maritimes Wednesday night. High pressure will then build to the south through Friday, moving into the western Atlantic this weekend. Low pressure will then approach from the west early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Minor adjustments made to forecast based on latest conditions. High pressure continues to push offshore today. This will allow weak low pressure and associated cold front to approach from the west. Most of any light snow or flurries today should be fall across far northwestern portion of the CWA (Lower Hudson Valley and NE NJ). Little if any snow accumulation. As such, have backed up the start time of the winter weather advisory for portions of NJ and the Lower Hudson Valley til 4 pm. Otherwise, expect cloudy skies today. Temperatures today climb into the lower and mid 30s, warmer closer to the coast. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Winter Weather Advisories in effect for Northeast New Jersey, the Lower Hudson Valley, Southern Connecticut and the Northern portion of NYC for late this afternoon through Wednesday. Low pressure and associated cold front approach the western portion of the CWA tonight, with the low passing just north of the region. Meanwhile, a second area of low pressure develops south of Long Island tonight, and passes east of Montauk early Wednesday afternoon. The combination of these two system will bring precipitation to the region. Highest confidence for snow is north and west of NYC, while the potential for mixed p-types reduces confidence for the city into Long Island and coastal Connecticut. Expecting the precipitation to remain mostly all snow through midnight, then as the developing low approaches, it should bring some warmer air into the area to change precipitation over to rain or a rain/snow mix across much the Long Island, NYC and portions of Coastal CT. The changing p-type has made forecasting snowfall amounts somewhat difficult, especially right along the rain/snow line. For now, thinking the highest snowfall totals will be across the Lower Hudson Valley and southern CT, with the exception of southern New London County. These areas have 4-6 inches of snow forecast. Across NE NJ and the northern portions of NYC, looking at 3-4 inches. The Southern portion of NYC and Nassau, 2-3 inches are expected. and across Suffolk county on Long island, up to 1 inch. The heaviest precipitation is expected to fall Tuesday night into Wednesday morning, then taper off from west to east during the mid to late afternoon and early evening. 16/00Z forecast guidance has come into better agreement with the track of the low, however a shift to the west, would increase the chance for more rain across NYC and CT and potentially increase snowfall amounts across the interior. A track farther offshore, would increase snowfall amounts closer to the coast. Lows tonight fall into the middle and upper 20s across the interior, while coastal locations fall into the lower 30s. On Wednesday, highs climb into the lower 30s across the interior, with middle 30s closer to the coast. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... On the heels of an upper trough passing offshore early Thursday, a progressive southern branch of the polar jet will become dominant across the lower 48, with a a gradual warmup as the air mass transitions to Pacific origin. Daytime highs on Thursday will be or just above near freezing, rising to the upper 40s and lower 50s by Sunday/Monday. Conditions will be mainly dry as a large area of high pressure over the Lower Mississippi Valley translates slowly east and passes to the south through the week and offshore this weekend. A southern branch storm system then approaches late in the weekend into early next week, with a surface low forecast to track up into the Great Lakes. The trailing cold front moves through Monday night. This is likely to be a rain event with a deep layered southerly flow preceding the system, but with cold sfc air initially there could be some mixed precip inland late Sunday night/Monday morning inland NW of NYC. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/...
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High pressure retreats to the northeast today. An area of low pressure approaches from the south into tonight, then tracks to near Cape Cod by early Wednesday afternoon. For most terminals apart from KSWF, VFR conditions with CIGS around 030-035 may persist through about 20Z before lowering to MVFR. Conditions then lower to IFR as precipitation becomes steadier after midnight. Expect any precipitation to largely hold off until after sunset, except at KSWF where occasional snow showers will be possible through the day. Expect all snow at KSWF, KEWR, KTEB and KHPN. A rain/snow mix or perhaps all rain will be possible for KLGA/KJFK/KBDR, with all rain more likely at KGON/KISP. All sites may receive light snow as the system departs Wednesday morning. Light and variable winds become SE at less than 10 kt at city terminals this afternoon, then light and variable again this evening, before becoming NE at less than 10 kt tonight. NY Metro Enhanced Aviation Weather Support... Detailed information...including hourly TAF wind component fcsts can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Winds generally light and variable at times. Spotty MVFR ceilings possible for early afternoon. Low confidence in precipitation type with snow totals around 3 inches possible through Wednesday. The afternoon KJFK haze potential forecast is green...which implies slant range visibility 7SM or greater outside of cloud. KLGA TAF Comments: Winds generally light and variable at times. Spotty MVFR ceilings possible for early afternoon. Low confidence in precipitation type with snow totals around 3 inches possible through Wednesday. The afternoon KLGA haze potential forecast is green...which implies slant range visibility 7SM or greater outside of cloud. KEWR TAF Comments: Winds generally light and variable at times. Spotty MVFR ceilings possible for early afternoon. Low confidence in precipitation type with snow totals around 3 inches possible through Wednesday. The afternoon KEWR haze potential forecast is green...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Winds generally light and variable at times. Spotty MVFR ceilings possible for early afternoon. Low confidence in precipitation type with snow totals around 3 inches possible through Wednesday. KHPN TAF Comments: Timing in changes to wind speed and direction could be off +/- 1-2 hours. Snow totals around 4 inches through Wednesday. KISP TAF Comments: Winds generally light and variable at times. Spotty MVFR ceilings possible for early afternoon. Primarily rain expected through occasional mixing of snow possible, along with snow as system departs Wednesday morning. Snow totals around 1 inch or less. .OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY... .Wednesday...IFR likely, with LIFR possible. Light snow expected, except rain or a rain/snow mix at Long Island/Eastern CT terminals and possibly KJFK/KLGA. Conditions improve to VFR late at western terminals. .Wednesday night-Thursday...VFR. NW-WNW winds G15-25KT possible. .Thursday night-Saturday...VFR. WSW-W winds G15-20KT possible Thursday night-Friday.
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&& .MARINE... SCA in effect for the ocean waters as seas remain 4-5 ft. Ocean seas increase a bit more tonight. Flow returns to a NW direction and begins to gust late on Wednesday, continuing into Thursday night. Small craft wind gusts and marginal seas will be likely on the ocean waters through Thursday night with a chance of small craft gusts across eastern Long Island Sound and the eastern Long Island bays. Friday through the weekend winds and seas will be below SCA levels as high pressure builds to the south and a weaker pressure gradient resides across the forecast waters. && .HYDROLOGY... No significant hydrologic impacts are expected. && .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... CT...Winter Weather Advisory from midnight tonight to 6 PM EST Wednesday for CTZ005>012. NY...Winter Weather Advisory from 4 PM this afternoon to 4 PM EST Wednesday for NYZ067>070. Winter Weather Advisory from midnight tonight to 6 PM EST Wednesday for NYZ071>073. NJ...Winter Weather Advisory from 4 PM this afternoon to 4 PM EST Wednesday for NJZ002-004-103-105-107. Winter Weather Advisory from midnight tonight to 6 PM EST Wednesday for NJZ006-104-106-108. MARINE...Small Craft Advisory from midnight tonight to 6 PM EST Wednesday for ANZ355. Small Craft Advisory until 6 PM EST Wednesday for ANZ350-353. && $$ SYNOPSIS...BC/Goodman NEAR TERM...BC/DW SHORT TERM...BC LONG TERM...Goodman AVIATION...MD/Maloit MARINE...BC/Goodman HYDROLOGY...BC/Goodman EQUIPMENT...

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