899 FXUS61 KBTV 150522 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1222 AM EST Sun Dec 15 2019 .SYNOPSIS... Deepening low pressure will lift through the region tonight with areas of light rain and snow expected. As the low pulls away on Sunday colder air arrives with gusty west winds expected and snow showers gradually ending across the northern mountains. Monday's weather looks cold and tranquil, before a period light accumulating snow arrives on Tuesday. && .NEAR TERM /UNTIL 1 PM THIS AFTERNOON/... As of 1217 AM EST Sunday...Fcst remains on track as 977mb low pres lifts across southern Canada and brisk southwest winds and deformation precip impacts northern NY. All elements are covered well in fcst early this morning. Previous Discussion...Quite the complex forecast over the next 12-18 hours as deepening sub-990 mb surface low lifts north directly through the forecast area. We remain in a broad dry slot as of mid-afternoon with only limited pcpn returns across the area. As the low passes this evening into tonight developing deformation precipitation band evolves across northern NY counties and gradually eases into northern VT before pulling away into the morning hours on Sunday. Boundary layer thermal profiles will be marginal for accumulating snows in this band this evening, but enough dynamical cooling and increasing cold thermal advection develops on the back side of the departing low to lead to a changeover by the overnight hours in the Dacks/SLV and far northern Greens. Accumulations to range from 2-5 inches in the northwestern Dacks where Winter Weather Advisories will remain in place. Elsewhere, 1-2 inches are expected in the SLV/higher southern Greens and 2-4 inches in the higher elevations of the northern Greens. The Champlain Valley and much of eastern/southern VT to see little if any accumulation. Temperatures to hold quite mild through mid- evening (40s) as the low passes, then slowly fall through the 30s overnight. By later tonight into Sunday, the westerly pressure gradient tightens sharply as the deepening low lifts away and prior forecaster's idea of increasingly gusty west flow still looks reasonable at this point. Sustained winds from 15 to 25 mph with gusts from 30-45 mph or so will be maintained during the daylight hours on Sunday accordingly. This is just shy of wind advsy criteria, but these speeds should be strong enough to create areas of blowing snow in the WWA area as well as elevated northern terrain. Some isolated power outage issues will also be possible in favored downslope areas on the eastern slopes of the Dacks/Greens. During this period snow shower activity slowly wanes and becomes increasingly confined to higher northern terrain with only light additional accumulation. High temperatures to hold fairly steady in the 30s. West to northwest winds remain fairly gusty into Sunday evening, but gradually relax by later at night as shortwave ridging moves into from the Ohio Valley/Great Lakes. Skies should trend partly cloudy to mostly clear as temperatures drop into the 5 to 15 above range with some variability. && .SHORT TERM /1 PM THIS AFTERNOON THROUGH MONDAY NIGHT/... As of 332 PM EST Saturday...High pressure will move from west to east across the area on Monday with dry weather expected along with high temperatures a few degrees below seasonal normals. The high will be far enough east Monday night to allow clouds and precipitation to begin spreading into the region...especially after midnight. This will be in response to a low pressure system developing to our south and west. Warm air advection/frontogenesis will be increasing over the area to begin increasing precipitation chances. Best chance for accumulating snow will be during the day on Tuesday. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 332 PM EST Saturday...Looking at a widespread light to moderate snowfall across the area on Tuesday. Low pressure essentially tracks east and northeast across Long Island. Feature is progressive and never becomes a deep low. 850 and 700 mb frontogenesis north of the surface low will likely enhance the snow over our area. At this time the central and southern sections of Vermont will be in the area where 850/700 mb frontogenesis will be maximized. Favorable snow growth not lined up at this time and with the system being on the progressive side are limiting factors to heavy snow. Nevertheless could see 2 to 5 inches across south central Vermont with decreasing amounts as you head northwest across the area. The snow should end quickly Tuesday night. Wednesday has the potential to be another active day. Well defined upper low drops down from Canada on Wednesday helping to enhance dynamic forcing over the region. But what really stands out is the cooling along with this system helps to create dry adiabatic lapse rates approaching 15,000 feet. The depth of this dry adiabatic lapse rate would support more than enough instability for convective snow showers. And the increasing dynamic support would help create a greater areal coverage of the snow showers...which would have the potential to produce quick bursts of heavy snow and whiteout conditions. System will definitely need to be monitored. Upper low moves east of the area Wednesday night and northwest flow aloft develops on Thursday and Friday for noticeably colder temperatures along with drier weather across the region. && .AVIATION /05Z 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. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...Winter Weather Advisory until 7 AM EST this morning for NYZ026- 027-087. Winter Weather Advisory until 1 PM EST this afternoon for NYZ029>031. && $$ SYNOPSIS...JMG NEAR TERM...JMG/Taber SHORT TERM...Evenson LONG TERM...Evenson AVIATION...Taber