Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 121444 AFDOKX Area Forecast Discussion National Weather Service New York NY 944 AM EST Tue Dec 12 2017 .SYNOPSIS... Low pressure passes to the north today moves into the Canadian Maritimes tonight into Wednesday night. High pressure builds overhead Wednesday night. An Alberta Clipper will pass through early Thursday. Developing low pressure will move up the east coast late Friday into early Saturday. High pressure builds in from the south Saturday into Sunday, followed by a low pressure system Sunday night into Monday. High pressure builds back on Tuesday. && .NEAR TERM /TODAY/... Warm front has pushed through coastal sections so far this morning and will continue to head north through most of the rest of the area. Rain expected ahead of this front with scattered showers behind it and ahead of an approaching cold front. SPS has been issued for Orange County to address areas of freezing rain primarily north of I-84. Temps there should warm above freezing within an hour. Cold front arrives late in the day west of the Hudson river. There will be a chance of showers and gusty winds behind it. High temperatures today above normal. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... The surface low will move into northern New England and then into the Canadian Maritimes through Wednesday night as the upper level low swings through, just north of the area. Colder air will also move in behind the low. This will change rain back to snow, from northwest to southeast tonight into Wednesday morning. However, there will only be a slight chance for precipitation with no accumulation expected. As the low pulls away from the area, it will quickly intensify, allowing for a strong pressure gradient to set up. Conditions will become windy late tonight into Wednesday, with gusts by late morning into the afternoon hours of 35 to 45 mph. There may be an isolated gusts to more than 45 mph, therefore, Wind Advisory is not needed at this time. Highest winds will occur across the Twin Forks of Long Island. Strong cold air advection will continue for Wednesday. Temperatures not expected to get out of the 20s for inland areas, with highs around or just above freezing for coastal areas. Some ocean affect snow showers may find their way inland for the South Fork of Long Island late Wednesday morning into the early afternoon before ending by mid afternoon. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Dry, cold and windy conditions expected Wednesday night as high pressure builds overhead. Temperatures overnight on Wednesday will be in the teens inland and lower 20s along the coast. A clipper low will pass south of the area on Thursday bringing a low chance for snow showers across the area, with only light accumulations expected. High temperatures on Thursday will be in the upper 20s to lower 30s. A coastal low is then expected to move up the east coast Friday night and into early Saturday. How much snow we get from this system depends on how close the low tracks near the coast. Latest model runs are not in agreement with timing or position, therefore will continue with chance pops across the area. A ridge builds in behind the coastal low Saturday into Sunday. Winds will turn to the southwest, allowing for warmer temperatures across the area for the weekend. Low pressure may impact the area later Sunday into Monday...bringing a chance for precipitation with temperatures on Monday in the upper 30s to lower 40s. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... A warm front continues to lift north of the terminals this morning, followed by a cold front moving across the area this afternoon and evening. VFR, at times MVFR ceilings and visibilities, are expected through much of the late morning and afternoon period. It should be warm enough for the precipitation to fall in the form of plain rain at all the area terminals. After the cold frontal passage this afternoon and evening, cold air will work back into the region and snow showers will be possible, even at the coastal terminals. Southerly winds initially shift to the southwest by afternoon, then to the west to northwest behind the cold front. Occasional gusts possible this afternoon to 20 kt, Then gusts begin in earnest late afternoon/early evening. There is the potential for winds to gust as high as 30 KT, especially during the evening. The gusts continue through the evening and into Wednesday morning, where gusts could reach as high as 40 kt late at the 30 hour TAF sites. 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: Southerly winds gust to near 20 KT, then winds shift to the SW around 17Z. NW gusts 25-30 KT possible this evening. The afternoon KJFK haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KLGA TAF Comments: Southerly winds gust to near 20 KT, then winds shift to the SW around 17Z. NW gusts 25-30 KT possible this evening. The afternoon KLGA haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KEWR TAF Comments: Southerly winds around 10 kt late this morning, then winds shift to the SW around 17Z and begin to gust to 20 kt this afternoon. NW gusts 25-30 KT possible this evening. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Southerly winds around 10 kt late this morning, then winds shift to the SW around 17Z. NW gusts 25-30 KT possible this evening. KHPN TAF Comments: Southerly winds around 10 kt late this morning, then winds shift to the SW around 17Z. NW gusts 25-30 KT possible this evening. KISP TAF Comments: Southerly winds around 10 kt late this morning, then winds shift to the SW around 17Z and begin to gust to 20 kt this afternoon. NW gusts 25-30 KT possible this evening. .OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY... .Wednesday...VFR, with a chance of MVFR in snow showers. W-NW winds G30-40KT possible. .Wednesday night-Thursday night...VFR. W-SW winds G15-25KT possible. .Friday...MVFR possible with snow. W-NW winds G15-20KT possible. .Saturday...VFR. NW winds G15-20KT possible. && .MARINE... SCA conditions expected over all waters today as deepening low pressure approaches from the west, increasing the pressure gradient between the low center and the high center out into the Atlantic. Cannot rule out a gale gust or two during the day, but as a front approaches, winds may temporarily diminish. By nighttime Tuesday, westerly winds pick up behind the deepening low as it passes north across New England. Waves will build over all waters. 5 to 7 ft expected over the ocean waters by the end of the day, and building to 10 to 12 ft over the ocean waters by the end of the day Wednesday. Gale Watches have been converted to Warnings as winds will gust to greater than 34 kt over all waters. Highest winds expected over the eastern ocean zone, where gusts just over 45 kt possible by late in the day today. Gale Warning for the ocean zones starting late tonight, and over all waters for Wednesday. A Gale Warning remains in effect for all waters Wednesday night. SCA conditions will likely continue into Thursday morning for most of area waters. Seas subside below SCA levels by Thursday night with the pressure gradient weakening and remaining below SCA conditions through the end of the week. A coastal storm may then impact the waters Friday night into Saturday with possible SCA conditions developing. && .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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 AM EST Wednesday for ANZ330-335- 338-340-345. Gale Warning from 6 AM Wednesday to 6 AM EST Thursday for ANZ330-335-338-340-345. Small Craft Advisory until 1 AM EST Wednesday for ANZ350-353- 355. Gale Warning from 1 AM Wednesday to 6 AM EST Thursday for ANZ350-353-355. && $$ SYNOPSIS...Fig/JP NEAR TERM...JC/JP SHORT TERM...JP LONG TERM...Fig AVIATION...BC/PW MARINE...JC/Fig/JP HYDROLOGY...Fig/JP EQUIPMENT...

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