Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 111433 AFDOKX Area Forecast Discussion National Weather Service New York NY 933 AM EST Mon Dec 11 2017 .SYNOPSIS...
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High pressure briefly builds today. Low pressure will then pass across the Great Lakes tonight, while an associated warm front lifts through Tuesday morning. A strong cold front passes in the afternoon. Low pressure will move into the Canadian Maritimes Tuesday night into Wednesday night, with brief high pressure building across the area in its wake. A weak Alberta Clipper passes to the south on Thursday, followed by a low pressure system passing off the coast late Friday into Friday night. High pressure returns for the weekend.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Upper shortwave passing this morning. Westerly fetch producing clouds across the LI sound seen on visible and radar, as shortwave passes. Otherwise, sunshine will give way to an increase in clouds later today. Winds diminish as high pressure begins to briefly build across the area. High temperatures today will top out in the upper 30s to lower 40s per latest hourly guidance.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
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Low pressure moves across the Great Lakes tonight into Tuesday morning. The associated warm front approaches the area from the south late tonight into Tuesday with increasing chances of precipitation, followed by a strong trailing cold front Tuesday afternoon. Warm advection ahead of the main portion of the storm will make this a mixed precip event. Rain is forecast for the city, adjacent suburbs and coastal section, although some snow can mix in at first. Across inland areas, snow or a snow/rain mix changes over to rain as Temperatures rise during the morning hours on Tuesday. Snow accumulations expected to be 1 or 2 inches for the northern suburbs, with 2 to 3 inches expected further north across Orange County. Less than an inch is expected anywhere else where snow manages to accumulate. Highs on Tuesday will be in the upper 30s to lower 40s inland and mid to upper 40s along the coast, with even some 50 degree readings for Long Island.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... A period of brisk weather is anticipated Tuesday night into Thursday as an intensifying low pressure system moves towards the Canadian Maritimes. With the tightening pressure gradient on the back side of the low, strong cold advection combined with sustained winds around 20-30 mph and gusts above 40 mph will lead to wind chill values in the single digits to teens on Wednesday, and largely the single digits to near zero Wednesday night. Although some moderation will occur on Thursday as flow backs to the WSW ahead of the next system, temperatures will remain well below climatological normals, with cold wind chill values in lingering breezy flow. Overall, a blocking pattern with low pressure anchored over the East Coast will continue a period of below normal temperatures and above normal precipitation as a series of waves rotate around the broader low. Chances of precipitation increase again into Friday as the subtropical jet shifts northward, combining with polar energy and leading to the development of a coastal low. The general track and intensity of the low will need to be monitored, but expected at least a slight chance of snow showers across the interior and perhaps a rain/snow mix along the coast into Friday night. Gusty flow and below normal temperatures will once again be possible as the low departs, with a slow moderation occurring through the weekend as high pressure builds across the area. && .AVIATION /15Z MONDAY THROUGH FRIDAY/...
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A cold front will move across the area today. VFR today and early tonight. Cigs fall to MVFR late in the TAF period, mainly after 09z Tuesday as a warm front pushes north of the area and associated low pressure system passes north of the area. precipitation starts after 06z, mainly in the form of a mix of rain and snow for most terminals, except KSWF, where precipitation should be all snow. As warmer air works into the the coastal locations, precipitation should quickly change over to all rain. Interior locations should stay snow through at least 12z Tuesday. Generally westerly winds today. There may be a few occasional gusts this morning, then gusts become more frequent during the afternoon with speeds around 20 kt. Gusts will end after 23Z. Tonight, winds become more southerly and remain less than 10 kt. 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: Gusts this afternoon may be occasional. The afternoon KJFK haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KLGA TAF Comments: Gusts this afternoon may be occasional. The afternoon KLGA haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KEWR TAF Comments: Gusts this afternoon may be occasional. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Gusts this afternoon may be occasional. KHPN TAF Comments: Gusts this afternoon may be occasional. KISP TAF Comments: Gusts this afternoon may be occasional. .OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... .Tuesday...MVFR or lower possible with a wintry mix to rain at northern terminals and rain at southern terminals. Conditions improve to VFR Tuesday afternoon. SE-SW winds G15-25KT possible. .Tuesday night-Wednesday...Mainly VFR, with a chance of MVFR in snow showers. W-NW winds G20-35KT probable. .Wednesday night-Thursday night...VFR. W-SW winds G15-25KT possible. .Friday...MVFR possible with snow. W-NW winds G15-20KT possible.
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&& .MARINE...
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As high pressure begins to build across the area, gusts will gradually begin to diminish, with seas slowly subsiding on the ocean waters later today. Winds and seas then increase again on Tuesday, with SCA conditions becoming likely on the area waters. By Tuesday night, gale- force winds will be possible as an intensifying low pressure system ejects into the Canadian Maritimes. Gusty flow and at least SCA-level conditions will continue into Thursday before gradually subsiding into Thursday night as flow weakens across the area. Relatively tranquil conditions persist through Friday before winds and seas increase into Friday night behind a departing low pressure system.
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&& .HYDROLOGY... No significant hydrologic impacts expected. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the air for an extended period of time. See our headline news on the web at: http:/weather.gov/nyc The Riverhead NOAA Weather Radio Station WXM-80 (162.475 MHz) is currently out of service. NWS technicians are working with Verizon to restore service. An estimated time of return to service is not currently known. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ350- 353-355.
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&& $$ SYNOPSIS...MD/Fig NEAR TERM...MD/Fig/PW SHORT TERM...Fig LONG TERM...MD AVIATION...BC/IRD MARINE...MD/Fig/PW HYDROLOGY...MD/Fig EQUIPMENT...

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