Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 021206 AFDOKX Area Forecast Discussion National Weather Service New York NY 706 AM EST Fri Dec 2 2016 .SYNOPSIS... Low pressure slowly moves across the Canadian Maritimes through tonight, then over the North Atlantic on Saturday. High pressure will build in over the weekend, pushing offshore Sunday night as a weak disturbance approaches. High pressure builds in late Monday through Tuesday. A frontal system approaches for the middle of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Over the last few hours, jet induced cirrus has been noted on IR imagery across eastern PA through the Lower Hudson Valley. These clouds are developing between a 300 hPa jet streak over New England and a 300 hPa jet streak over the TN Valley. This moisture can also be seen on NAM BUFKIT time heights. Have therefore increase sky cover a bit this morning where previous forecast had little to no clouds. Otherwise...the forecast is on track. Similar overall weather pattern across the northeast today as was observed on Thursday. Closed upper level low and its associated surface low will slowly move across the Canadian Maritimes. The flow over the region initially will be near zonal, but an upper trough and shortwave energy will pivot around the upper low and approach this afternoon. Stratocumulus/instability clouds will expand from NW to SE with scattered to broken sky coverage at times, especially this afternoon. Thinking any flurries/sprinkles will stay to the NW of the CWA, but it is not out of the question a few spill over into Orange county late. The pressure gradient will remain fairly tight between the low to the northeast and high pressure well to the west. Gusty west winds around 20 mph are forecast this afternoon and evening. A mav/met blend looks reasonable today with temperatures near normal in the upper 40s to near 50 degrees. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... Stratocumulus clouds are likely to linger tonight with the best coverage across the NW interior as upper trough and energy move across tonight. The boundary layer will remain well mixed tonight so breezy conditions continue. With lingering clouds and a mixed boundary layer, good radiational cooling conditions are not expected. Temperatures will fall into the lower 30s inland and middle to upper 30s elsewhere. Upper low moves further east on Saturday with NW flow setting up aloft. Winds at the surface will also veer to the NW as high pressure moves closer and the low over the Canadian Maritimes moves out into the north Atlantic. The pressure gradient remains tight between these two systems and BUFKIT profiles indicate a well mixed boundary layer up to around 4 kft. Wind gusts 20 to 25 mph are once again expected. Daytime heating and some instability in the boundary layer should promote the continuation of scattered to broken stratocumulus. These clouds in combination with a deeper NW flow should hold temperatures a few degrees cooler than Friday, in the middle and upper 40s. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... High pressure will move over the region Sunday, allowing the pressure gradient to decrease, and thus winds to diminish. In the upper levels, weak upper level ridge axis will move over the region. Despite increasing heights, temperatures will be cooler on Sunday as compared to Saturday with a deep layered northwest flow in place. Upper level short wave approaches Sunday night. However, it will de-amplify and weaken as it does so. So only slight chance POPs with light amounts of QPF expected Sunday night into Monday. Temperatures may be cold enough inland for some snow showers, but again, not expecting any accumulation since QPF will be light. High pressure builds in over the area Monday and retreats northeast Monday night. This allows a frontal system to approach from the southwest. Two areas of low pressure will form along this frontal boundary. One over the Southeast U.S. that will push off the Southeast Coast Tuesday night, then head east. The other will develop over the Ohio Valley and pass north of the area into Wednesday. Cold air damming signature noted for Tuesday, so precipitation may start off as snow inland again, then change over to rain, with a mixture of rain and snow Tuesday night. Again, QPF will be light. Model solutions diverge at this point, with the 00Z GFS being typically more progressive than the 00Z ECMWF. Thinking is that a warm front will lift north, or at least be in the vicinity on Thursday, allowing the chances for precipitation to continue through the latter part of the week, with conditions being warm enough for all rain everywhere at this point. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/...
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Strong low pressure will slowly drift east through the Canadian Maritimes today and offshore tonight. Meanwhile high pressure builds into the Ohio valley. VFR conditions. SCT-BKN cigs 4-5kft this afternoon. A few sprinkles possible late this afternoon/early eve for mainly northern terminals. Westerly gusts of 20-25 kt...generally left of 310 magnetic...will become frequent mid to late morning and continue through the day. Gusts expected to maintain through the evening push for NYC/NJ metro terminals...and likely for outlying terminals. A few peak gusts to 30 kt possible late aft into eve for NYC/NJ metro terminals. 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: Westerly winds today...prevailing direction expected to be left of 310 magnetic. Frequent gusts to 20-25 kt...with a few peak gusts to 30 kt possible this aft/eve. KLGA TAF Comments: Westerly winds today...prevailing direction expected to be left of 310 magnetic. Frequent gusts to 20-25 kt...with a few peak gusts to 30 kt possible this aft/eve. KEWR TAF Comments: Westerly winds today...prevailing direction expected to be left of 310 magnetic. Frequent gusts to 20-25 kt...with a few peak gusts to 30 kt possible this aft/eve. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Westerly winds today...prevailing direction expected to be left of 310 magnetic. Frequent gusts to 20-25 kt developing this afternoon. KHPN TAF Comments: No unscheduled amendments expected. KISP TAF Comments: No unscheduled amendments expected. .OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY... .Saturday...VFR. NW gusts 20-25 KT. Generally right of 310 magnetic. .Sunday...VFR. .Monday-Tuesday...VFR...possibly lower at times depending on the track of low pressure to the south.
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&& .MARINE... The waters remain between deep low pressure near the Canadian Maritimes and high pressure well to the west through tonight. High pressure moves closer on Saturday as the deep low moves into the north Atlantic. Gusty westerly winds will continue today. There will be a brief weakening of winds on the near shore waters with gusts averaging around 20 kt this morning. Some weakening of winds is briefly possible on the ocean as well, but seas will remain above 5 ft. However, wind gusts will increase by this afternoon to around 25 kt in the afternoon. Despite winds briefly weakening, the SCA will continue on all waters today. Winds will continue to reach SCA levels tonight on all waters. Gusty NW winds are likely on Saturday and the SCA may need to be extended through this time period by subsequent shifts. There is a small possibility for gale force gusts on the ocean Saturday. Confidence is too low at this time for a gale watch, but will highlight in an HWO. Ocean seas will likely remain near 5 ft. Generally, 5 ft waves on the ocean Saturday night will diminish and fall below SCA Sunday morning. Thereafter, waves will remain below 5 ft through Tuesday. Waves build late Tuesday, rising to at or just above 5 ft late Tuesday night as a frontal system approaches from the southwest. Winds remain above 25 kt Saturday night, but diminish to below SCA by Sunday morning and should remain below SCA through Tuesday. However, the approaching frontal system could allow for gusts to 25 kt, mainly on the ocean. Right now though, there is a low chance for this to occur. && .HYDROLOGY... No significant precipitation (greater than a half inch) is forecast through the middle of next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 AM EST Saturday for ANZ330-335- 338-340-345-350-353-355. && $$ SYNOPSIS...JP/DS NEAR TERM...DS SHORT TERM...DS LONG TERM...JP AVIATION...NV MARINE...JP/DS HYDROLOGY...JP/DS

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