Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 131957 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 357 PM EDT Tue Mar 13 2018 .SYNOPSIS...
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Widespread light to moderate snowfall is expected across the North Country through Wednesday as strong low pressure passes east off the New England coast, and an upper level trough moves over the region. Snow showers continue across the higher terrain Thursday into Friday before high pressure brings an end to precipitation area-wide on Saturday. Colder than normal temperatures will move in for early next week.
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As of 350 PM EDT a simple manner, it`s gonna snow pretty much the entire time. the tough part is how much. 12z guidance pretty similar in the big picture with copius moisture tapped off the coastal storm and coming in at us from the east as an upper low moves just south of here. Latest runs are actually a little wetter, though based on initial comparison of reality to model projections, the models are a bit wet. That said, the snowfall forecasts have been adjusted upward a slight bit over the period. Please refer to: for the latest snowfall forecasts and snowfall range probabilities. Looking for an overall widespread light snow tonight for most of the region, though as the upper low slides to the south, hi-res models are suggesting a deformation zone developing across portions of northern NY late tonight that could result in some locally moderate to heavy snow developing across northern Clinton and Franklin Counties in NY. That is something that will need to be monitored, as we may need a warning issued for that area. At this point will stick with the Winter Weather Advisory because we`ll have general 1-2" per 6 hour accumulations area wide. That is something easy enough to handle, so minimal impacts. Though roads could become snow covered late tonight. Precipitation transitions to more an upslope/orographic nature later Wednesday and Wednesday night. With the upper low near us tomorrow, the snow may take on a bit of a convective nature to it as well, which could result in locally brief heavier snows. Have to say that there is a good amount of uncertainty in this forecast. Snow-Liquid ratios will vary between 11:1 to 18:1, lower SLRs during the day and lower elevations. If we get any deformation happening, then 20:1 or better is not out of the question. Add that to the QPF liquid precipitation uncertainty, that results in great variation in what we may end up getting vs the forecast.
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&& .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 339 PM EDT Tuesday...Deep cyclonic flow continues as vertically stacked system over northern Maine slowly lifts toward the Canadian Maritimes. The combination of embedded vorts and ribbons of enhanced 850 to 700mb rh fields, along with favorable 925mb to 850mb upslope flow will continue to produce snow showers across northern dacks into northern/central VT on Thursday. Additional accumulation, especially thru 18z is likely on have continued to mention likely to cat pops for the western slopes/northeast Kingdom and northern dacks. Froude number >1 suggests unblocked flow, especially as sfc heating helps develop low level instability/lapse expect precip along and downstream of the summits on Thursday. Several additions inches of snow accumulation is likely, especially above 1500 feet. The upslope snow machine will finally weaken on Thurs aftn/evening as better moisture lifts into northern Maine, but snow showers will linger into the mountains thru Thursday Night. Have continued to mention likely pops northern Greens with developing cold air advection on brisk 850mb northwest winds of 30 to 40 knots. Progged 850mb temps between -6c and -8c Thursday support highs mainly in the 20s mtns to mid 30s valleys, especially with fresh snow pack and clouds...but values fall to -12c and -15c by 12z Friday. These values will support single digits summits to l/m20s warmer valleys...but if more clearing develops than expected lows will be much colder. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 310 AM EDT Tuesday...Decent coverage of snow showers/light snows across the north then slowly wane Thursday night and especially by Friday as occlusion and parent upper low pull further northeast and away from the area. Gusty flow continues with a modified polar front sweeping through the region and ushering in an unseasonably chilly airmass for the late week time frame. Did opt to go about 5 degrees below GFS MOS guidance for highs on Friday, keeping values mainly in the 20s in closer agreement to this morning`s ECWMF MOS guidance. Quiet weather then returns by Friday night and onward into Sunday and Monday of next week as modified polar high pressure settles across southern Quebec/Ontario and into northern New England. Skies should trend partly cloudy during this period as winds trend light over time. Decent radiational cooling effects should occur during overnight periods with lows in the teens to around 20, though could plausibly be lower into the single digits in favored colder northern mountain hollows. Time will tell. Corresponding highs through this period should top out on the seasonably cool side from the upper 20s to mid 30s in general, though again could be a tad cooler than my current forecast for Monday of next week if model blended 925 mb temperature profiles pan out to fruition. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... Through 18Z Wednesday...Widespread snow producing IFR conditions, with some brief periods of LIFR especially across portions of Vermont associated with the band of higher reflectivity detected by radar. Conditions will not change much for the next 18-24 hours. Expect most TAF locations to have visibilities to range from 1/2sm to 2sm. Could see some MVFR develop after 15z Wednesday across far southern sections as the steady snow turns more into snow showers. Winds will gust 15-20 knots, especially through this evening. Outlook... Wednesday Night: Mainly MVFR and IFR, with local VFR possible. Definite SN. Thursday: Mainly VFR, with areas MVFR and IFR possible. Likely SN, Chance SHSN. Thursday Night: Mainly VFR, with areas MVFR possible. Chance SHSN. Friday: Mainly MVFR, with areas VFR possible. Chance SHSN. Friday Night: Mainly MVFR, with areas VFR possible. Chance SHSN. Saturday: Mainly MVFR, with areas VFR possible. NO SIG WX. Saturday Night: Mainly VFR, with local MVFR possible. Slight chance SHSN. Sunday: Mainly VFR, with areas MVFR possible. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Winter Weather Advisory until 8 PM EDT Wednesday for VTZ001>012-016>019. NY...Winter Weather Advisory until 8 PM EDT Wednesday for NYZ026>031-034-035-087. && $$ SYNOPSIS...Nash NEAR TERM...Nash SHORT TERM...Taber LONG TERM...JMG AVIATION...Nash is the U.S. government's official web portal to all federal, state and local government web resources and services.