Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 150834 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 334 AM EST Sun Dec 15 2019 .SYNOPSIS... Gusty westerly winds are expected today across the North Country, along with scattered mountain snow showers. A few inches of additional snowfall can be expected, as temperatures slowly drop back into the 20s and 30s. Winds generally 20 to 35 mph with localized gusts up to 50 mph possible, which may cause a few isolated power outages. Quieter weather returns for Monday, before light snow returns for Tuesday and potential snow squalls on Wednesday of this upcoming week. Temperatures will be near seasonable levels to start the work week. && .NEAR TERM /THROUGH MONDAY/... As of 332 AM EST Sunday...Winter weather advisory continues for storm total snowfall of 3 to 5 inches of snow for the northern Adirondacks in New York until 18z. Wind advisory in effect through 00z Monday for eastern Adirondacks and portions of central, eastern, and northern Vermont, including the NEK for localized gusts up to 50 mph and potential isolated power outages. Sfc analysis shows powerful 974mb low pres quickly lifting toward eastern Canada, while brisk westerly winds prevail across our fa. Back edge of deformation precip is lifting acrs northern NY, with a transition to upslope/trrn focused snow showers will evolve this morning. Little change in storm total snowfall anticipated with 3 to 5 inches northern Dacks and 2 to 4 inches northern Greens through 18z today. Winds will be gusty from the west today, especially as deeper mixing develops under moderate llvl caa. Soundings show top of the mixed layer winds of 45 to 55 knots, while bottom values of 35 to 40 knots, which with perpendicular cross barrier/mtn flow will result in localized gusts to 50 mph today. The strongest winds will occur in the favorable downslope regions of the eastern Dacks and on the east side of the Green Mtns and Worcester Range in VT. The core of strongest 850 to 925mb winds occurs btwn 09z this morning and 18z today, but best mixing is from 15z-21z, which will represent the best time period for localized gusts to 50 mph. A few isolated power outages are possible, along with some small shallow rooted trees, especially given saturated soils. Moderate caa continues as 925mb temps range btwn -4c to 0c at 12z this morning, but quickly drop btwn -7c to -11c by 00z this evening, as a result of gusty westerly winds. Have the general idea of falling temps in the grids, with values starting in the 30s to near 40f, but dropping into the teens and upper 20s by evening. Any lingering snow will dissipate by tonight, as moisture profiles decrease and weak sfc high pres builds into our fa. Expect partly cloudy skies with temps dropping back single digits to near 20f, warmest values near Lake Champlain. Monday is relatively quiet with slightly below normal temps and much lighter winds. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... As of 332 AM EST Sunday...For Monday night, increasing clouds with lows in the lower 20s to mid teens. Heading into Tuesday, forecast guidance has trended slower and further south with regards to the surface low track. Where models disagree this evening is how far the precipitation shield extends north. One thing our region will be combating is low- level dry air. At the time of the best saturation in the dendritic growth zone towards Tuesday morning, there will be low-level dry air in place with subsidence as well. Anticipate virga to begin the day on Tuesday. Once the lower levels become adequately saturated late morning/early afternoon, we should begin to see snow fall across most areas, though the St. Lawrence Valley will be the most likely to miss out. Seeing several mixed signals with regards to the snow ratios. The Cobb technique indicates values close to 15:1, and the depth of the dendritic growth zone is nearly 5000ft. However, the aforementioned dry air initially will result in some sublimation, and by the time everything becomes well saturated, the better vertical motion starts to exit the region. The latest forecast amounts still looks good for 2"-4" across south- Central Vermont with pockets of 5" possible and then 2" or less, especially as you head northwest towards the St. Lawrence Valley. Highs will top out in the mid 20s to near 30. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 332 AM EST Sunday...Wednesday will begin as a rather benign day, but that will quickly change as a strong upper low that is nearly pushing sub 500hPa heights advects into the region. A clipper low will deepen as it moves southeastward towards BTV and draws moisture from Lake Ontario ahead of it. Forcing should be vigorous ahead of the strong baroclinic zone from the strong cold air behind it. Forecast soundings are certainly impressive. It will not be long before this event falls within the scope of higher resolution models, and it will be closely monitored, as snow squall potential already looks quite high. Behind the system, very cold temperatures with lows in the single digits above and below zero and highs struggling to get into the teens for a couple days. We will moderate over the weekend with very dry conditions behind the polar front. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... Through 06Z Monday...IFR conditions will prevail at MSS until 9z and thru the first 6 hours at slk for the combination of low cigs and vis btwn 1-2sm in light snow. Latest radar trends show snow lifting at mss by 09z with conditions improving to mvfr. Elsewhere, strong gusty southwest winds will result in improving conditions at PBG/BTV with mainly vfr, while lingering cigs in the mvfr range impacts MPV/RUT. Winds generally southwest to west at 15 to 25 with localized gusts up to 30 to 35 knots likely on Sunday btwn 12z and 20z. Intervals of snow showers will persist most of the day at slk along with periods of ifr vis/cigs. Areas of moderate turbulence likely given cross runway flow at btv and winds perpendicular to the trrn across all our taf sites. Outlook... Monday: VFR. NO SIG WX. Monday Night: VFR. Chance SN. Tuesday: Mainly VFR, with areas MVFR and IFR possible. Likely SN. Tuesday Night: Mainly MVFR, with local VFR possible. Chance SHSN. Wednesday: Mainly VFR, with areas MVFR possible. Chance SHSN. Wednesday Night: VFR. Slight chance SHSN. Thursday: VFR. NO SIG WX. && .MARINE... Lake wind advisory has been issued for west winds of 15 to 25 knots with localized gusts up to 30 knots possible. Winds should weaken this afternoon as powerful low pressure shifts away from the region. Wave generally in the 1 to 3 foot range, given the short fetch associated with the westerly wind component. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Wind Advisory until 7 PM EST this evening for VTZ003-004- 006>008-010-012. NY...Wind Advisory until 7 PM EST this evening for NYZ031-034. Winter Weather Advisory until 1 PM EST this afternoon for NYZ029>031. && $$ SYNOPSIS...Taber NEAR TERM...Taber SHORT TERM...Haynes LONG TERM...Haynes AVIATION...Taber MARINE...

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