Area Forecast Discussion
Issued by NWS Burlington, VT

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498 FXUS61 KBTV 190850 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 350 AM EST Sun Nov 19 2017 .SYNOPSIS...
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Strong low pressure will sweep across the area today with strong and gusty winds as temperatures trend colder and steadier rains taper to snow showers. Relatively quiet weather is expected from Monday onward through much of next week with early indications suggesting a good travel day for the upcoming Thanksgiving holiday.
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&& .NEAR TERM /THROUGH MONDAY/...
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As of 350 AM EST Sunday...Deepening 982 mb surface low near KART early this morning will take an expected climo track through the St. Lawrence Valley today before exiting quickly toward the Gaspe Penninsula by this evening. The forecast is predicated on this scenario and largely follows persistence from our prior forecast showing steadier rains ending from southwest to northeast this morning as the system`s sharp cold front sweeps across the area. Strong cold thermal advection will quickly follow the front as winds shift west/northwesterly and trend quite gusty under a deeply mixed boundary layer. Perusal of area forecast soundings continue to support maximum gusts from 25 to 40 mph with a few gusts near 45 mph along the eastern slopes of the Adirondack and Green Mountains where isolated power outages will be possible. This seems plausible given robust post- frontal 3-hourly pressure rises from 5 to 9 mb from late morning into this afternoon. As colder air pushes into the area, lingering precipitation will trend more showery in nature and quickly transition to snow across northern NY and the northern mountains of VT where minor accumulations from a dusting to 2 inches or so will be possible. Little accumulation is expected in the Champlain and lower CT River Valleys. Temperatures will take on a non-diurnal trend and will be somewhat challenging as readings gradually fall into the afternoon. Using a blend of our prior forecast and this morning`s BTV 4km WRF output supports morning highs in the 30s across the Dacks/SLV and lower to mid 40s in VT before readings falling into the upper 20s to lower 30s for most spots by early evening. By tonight any lingering snow showers across the northern high terrain will gradually end as brisk northwest flow abates slightly. Any additional accumulations will be minor at best as low temperatures bottom out from the mid teens to lower 20s under variably cloudy skies. Brisk and seasonably cold weather then continues into Monday, though outside a few mountain flurries dry weather is expected as surface high pressure builds east from the Great Lakes and skies gradually trend partly sunny by afternoon.
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&& .SHORT TERM /MONDAY NIGHT/... As of 154 PM EST Saturday...Deep cold trof rotating out of area during this period with building heights and zonal flow and surface ridging while the main surface high is located along the mid-Atlantic coast. Primarily dry and unseasonably cool with gusty NW winds of Sun-Sun ngt gradually diminishing and shifting W-WSW. Highs 25-33. Return flow Monday night means not as cold as Sun ngt-Mon morning with the exception of eastern VT and lows in the 20s with teens in NE VT and deep Adirondacks Vlys. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 154 PM EST Saturday...Primarily a very broad cyclonic flow pattern for the period with very minor disturbances and slight roller coaster of temperatures but largely below normal. There is an outside threat of a coastal storm Wed-Wed ngt but most current indications are keeping this a mid-atlantic and then out to sea storm with no impacts for our area but still worth monitoring for the next few days. Tuesday: High pressure sliding offshore for a return flow ahead of northern stream shortwave for moderating temperatures in the 40s. Northern shortwave and cold front move across area Tue ngt and largely exit by Wednesday. This will bring rain to mixed rain/snow showers and colder air once again. Wednesday: Cold front exiting region, although we still must look to our south and model trends about possible coastal. Currently, exiting drier conditions with some mountain snow showers possible with temperatures in the 30s/40. Thanksgiving: Quiet with surface high in control but the eventual approach of another northern stream shortwave by Thursday night. Currently dry with temperatures in the 30s. Thursday Night/Friday: Much of the energy with northern stream shortwave is in Canada but can`t rule out some isold/sct snow showers, especially in the mountains. Lows in the 20s and Highs in the 30s, a tad milder than Turkey day. Friday night/Saturday: We return to a more zonal flow with another minor shortwave and surface reflection moving along the Great Lakes and international border with some decent warm-air advection ahead of it for light snow/snow showers Friday night and scattered rain/snow showers on Saturday with temperatures in the mid-upper 30s. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... Through 06Z Monday...Mix of MVFR/IFR/LIFR through 12-15Z time frame, trending mainly VFR/MVFR thereafter as deep low pressure passes through the region. Most prevalent IFR/LIFR at KMPV/KSLK. Periods of light rain to continue across the entire area through 12-15Z before strong cold front crosses the region and precipitation trends more showery. A period of post-frontal IFR shsn possible at KSLK/KMSS for a short window in the 15-19Z time frame with other terminals trending mainly precipitation-free. Winds mainly south/southeasterly from 6 to 12 kts (northeasterly at KMSS) through 12-15Z, trending westerly 10 to 20 kts and gusty to 30 kts behind the cold front thereafter. Outlook... Monday: VFR. NO SIG WX. Monday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA, Slight chance SHSN. Wednesday: Mainly VFR, with areas MVFR possible. Chance SHRA, Chance SHSN. Wednesday Night: Mainly VFR, with areas MVFR possible. Slight chance SHSN. Thanksgiving Day: Mainly VFR, with local MVFR possible. Slight chance SHSN. && .MARINE...
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As of 350 AM EST Sunday...A Lake Wind Advisory remains in effect for today as southerly winds shift sharply to the west/northwest by late morning and increase into the 15 to 25 knot range by this afternoon as a strong cold front sweeps across the area. This will create significant wave heights in the 2 to 4 foot range with a moderate chop. These conditions may prove hazardous to those operating small craft, especially on the eastern half of the broad lake and in Vermont bays/inlets with westerly exposures. Gusty northwest winds will abate slightly later this evening into Monday.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...SLW LONG TERM...SLW AVIATION...JMG MARINE...JMG

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