Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 061433 AFDOKX Area Forecast Discussion National Weather Service New York NY 933 AM EST Tue Dec 6 2016 .SYNOPSIS... High pressure builds over the area this morning, then retreats to the northeast this afternoon. Low pressure will track off of Cape Hatteras tonight, and southeast of Long Island and out to sea on Wednesday. A series of cold fronts will move southeast across the region through Friday followed by cold canadian high pressure Saturday Low pressure will approach Sunday and move across the area early next week. && .NEAR TERM /UNTIL 3 PM THIS AFTERNOON/...
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High pressure drifts over the Tri-State Region this morning, and over Maine this afternoon. The result will be mid and high clouds overspreading the area from south to north this morning. Have adjusted the cloud forecast accordingly with this update. The guidance was in good agreement for temperatures, so a blend was used.
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&& .SHORT TERM /3 PM THIS AFTERNOON THROUGH 6 PM WEDNESDAY/... Low pressure will develop along a warm front late today over the Southeast, with the low deepening off of Cape Hatteras by around 00Z. The low will then hook to the right after 6Z and track out to sea. The NAM, GFS and ECMWF were tightly clustered on the track and intensity of the low. The thermal profiles progged are minimally supportive of snow with the system. This quickly eliminates the coasts from snow chances with a mild boundary layer on easterly component flow. Across the interior, any accumulating snow will depend on wet bulbing and elevation. As a result, only minor snow amounts are expected for the majority of the forecast area at this time. The main exception is across Orange county, where it appears they are far enough inland to avoid a marine influenced boundary layer, have enough deep lift to produce moderate precipitation rates and maximize the wet bulb effect, and have some elevation to cool the low levels orographically. Because of this, a Winter Weather Advisory has been issued for the county. Much of the area could only see a slushy inch or so, but elevations over a thousand feet could pick up around 4 inches if everything comes together as currently forecast. As the lift weakens after 6Z and dry air aloft spills in, the precipitation looks to transition to light rain and drizzle early Wednesday morning into the early afternoon. There is a low chance that some pockets of freezing drizzle develop across the interior before 12Z. The most likely spot is where the advisory has already been issued for snow. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Little change in the long term as a closed upper low remain across southeastern Canada Wednesday night through Friday. A shortwave will rotate around the closed low bringing a cold front and surface trough moving through the Mid Atlantic Thursday. This may result in isolated to scattered rain/snow showers, along with a cold air mass. This cold front will bring temperatures around 5 to 10 degrees below normal by the end of the week. The upper low opens and moves out late Friday and Friday night with weak upper ridging. The upper flow become nearly zonal across the continental United States Friday night and through the weekend. With high pressure moving off the northeast coast Sunday a return flow develops and warm advection sets up into Monday. The next shortwave to affect the area will move on shore of the Pacific northwest Friday night and quickly move across the country. Cyclogenesis occurs across the central plains Sunday into Sunday night with the low tracking through the Great Lakes. Precipitation Sunday night may start as snow inland and transition to rain Monday and will be dependent on how quickly the warmer air moves into the area. If a warmer layer moves in aloft before the low level cold air is scoured out there will be a chance for some freezing rain Sunday night. With the uncertainty did not include in the forecast at this time and leaned toward a warmer solution. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/...
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High pressure will move offshore this afternoon. Low pressure approaches from the southwest late today, passing to the south tonight. VFR with gradually increasing mid and high clouds today. MVFR conditions spread in from the SW around 00z as rain approaches the NYC metro. The rain and MVFR/IFR conditions sweep across the remainder of the area during the evening. Snow expected to at least mix with the rain at KSWF with the potential for a few inches of snowfall. NE winds will veer around to the ESE this afternoon, and then back to the E-NE tonight as low pressure moves off the Mid Atlantic coast. Gusts up to 20 kt expected at the coastal terminals tonight. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: Timing of MVFR/IFR conditions could be delayed 2-3 hours. KLGA TAF Comments: Timing of MVFR/IFR conditions could be delayed 2-3 hours. KEWR TAF Comments: Timing of MVFR/IFR conditions could be delayed 2-3 hours. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Timing of MVFR/IFR conditions could be delayed 2-3 hours. KHPN TAF Comments: Timing of MVFR/IFR conditions could be delayed 2-3 hours. KISP TAF Comments: Timing of MVFR/IFR conditions could be delayed 2-3 hours. .OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY... .Wednesday...MVFR/IFR in stratus, with slow improvement during the afternoon. .Wednesday night-Thursday night...VFR. .Friday-Friday night...VFR. NW winds 15-20 kt, gusts 25-30 kt. .Saturday...VFR. NW winds 15 kt gusts 20-25 kt.
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&& .MARINE... Northerly flow today will veer to the northeast and intensify tonight. A Small Craft Advisory has been issued for the ocean tonight into Wednesday for this, with an advisory for the Harbor for tonight. Elsewhere, winds and seas area expected to remain below small craft levels. Winds and seas will remain below SCA levels Wednesday night through Thursday as low pressure remains to the north across southeastern Canada. A cold front will move through Thursday and a strong and gusty northwest flow will develops. Thursday night SCA gusts develop on the ocean waters, and then during Friday winds increase, to near gale force on the ocean waters, and SCA gusts on the remainder of the forecast waters. SCA gusts continue into Friday night, then subside late as high pressure begins to build to the west. Saturday morning winds and seas are expected to be below SCA levels on all the waters as high pressure continues to build. Winds and seas increase once again early next week as another low pressure system moves across the area. && .HYDROLOGY... A half inch or less of liquid equivalent is expected tonight. Otherwise, no hydrologic impacts are anticipated the next 7 days. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...Winter Weather Advisory from 6 PM this evening to 6 AM EST Wednesday for NYZ067. NJ...None. MARINE...Small Craft Advisory from 6 PM this evening to noon EST Wednesday for ANZ350-353-355. Small Craft Advisory from 6 PM this evening to 6 AM EST Wednesday for ANZ338. && $$ SYNOPSIS...BC/JMC NEAR TERM...JMC/JC SHORT TERM...JMC LONG TERM...BC AVIATION...JM/DW MARINE...BC/JMC/JC HYDROLOGY...BC/JMC is the U.S. government's official web portal to all federal, state and local government web resources and services.