Area Forecast Discussion
Issued by NWS Burlington, VT

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
617 FXUS61 KBTV 191232 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 732 AM EST Sun Nov 19 2017 .SYNOPSIS... 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. && .NEAR TERM /THROUGH MONDAY/... As of 732 AM EST Sunday...Minor updates to capture latest hourly trends in temperatures/dewpoints as sharp cold front enters the Champlain Valley as of 730 am. Temperatures already falling steadily across the Adirondacks and St. Lawrence Valley where precipitation is transitioning to -sn/-shsn. Already had a report of 1" of snow in Massena so current forecast of light snow accumulations still appears on track. Have a great day. Prior discussion... 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 Peninsula 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. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... As of 400 AM EST Sunday...Monday night and Tuesday will feature drier weather, and increasing return flow bringing temps back above seasonal normals for Tue. Will still have a surface ridge over the area Monday night, therefore cool temps, clear skies and light winds expected. Increasing southerly return flow on Tue as ridge moves east of the region. Temps will edge into the 50s on Tue. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 400 AM EST Sunday...A cold front will cross our forecast area Tuesday night bringing scattered light rain and snow showers to the area and colder air for Wed. Have mentioned chance pops across our Northern New York zones for Tuesday night, then chance across Northern Vermont on Wednesday. Not a lot of moisture with this front as low passes well north of our region, but think we`ll see at least some scattered light showers. Rain showers will end as light mountain snow showers. We return to dry weather again for Thursday through Friday. Friday night through Saturday night will be our next chance at some weather. Another low will pass North of the region bringing scattered rain and snow showers to the area once again. GFS and ECMWF still differ quite a bit with track and timing of the low. Temperatures will trend back below normal for much of the week with a few chances for precipitation, but nothing significant. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... Through 12Z Monday...Mix of MVFR/IFR/LIFR through 15Z time frame, trending mainly VFR/MVFR thereafter as deep low pressure passes through the region. Most prevalent IFR/LIFR at KMPV/KSLK/KMSS. Periods of light rain to continue at eastern terminals through 12-15Z as strong cold front crosses the region and precipitation trends more showery. A period of post- frontal IFR shsn likely at KSLK/KMSS for a short window in the 13-19Z time frame with other terminals trending mainly precipitation-free so offered VCSH only after 16Z or so. Winds trending westerly from 270-290 at 10 to 20 kts and gusty into the 25 to 35 kt range in the 12-15Z time frame behind the cold front. This will create enhanced crosswind concerns at KPBG and KBTV terminals. Winds will abate somewhat after 00Z Monday but remain gusty. 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. Chance SHRA, Chance SHSN. Wednesday: Mainly VFR, with areas MVFR possible. Chance SHSN, Slight chance SHRA. Wednesday Night: Mainly VFR, with areas MVFR possible. NO SIG WX. Thanksgiving Day: Mainly VFR, with local MVFR possible. NO SIG WX. && .MARINE... 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. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...Neiles LONG TERM...Neiles AVIATION...JMG MARINE...JMG is the U.S. government's official web portal to all federal, state and local government web resources and services.