textproduct: Burlington

SYNOPSIS

In the wake of our Friday system, much quieter weather is expected on Saturday, before more winds develop on Saturday night into Sunday. Gusty channeled flow from south winds, locally up to 40 mph will be possible tonight as a clipper system rides north of the border. Mountain snow chances will continue through the weekend as a parade of quick moving system traverse the region through early next week. Seasonable to just above average temperatures and continued snow chances are likely heading into the holiday travel period.

NEAR TERM /THROUGH SUNDAY/

As of 139 AM EST Saturday... *A Wind Advisory remains in effect for portions of northern New York and areas east of the Green Mountains spine until 7 AM for gusts up to 45 to 50 MPH and additional isolated power outages.

An arctic boundary continues to slide to the southeast across northern and central Vermont with some enhanced areas of snow. The band has begun to weaken, but behind, much cooler air is advecting in with west northwest flow. While BTV current sits at 30, Plattsburgh is at 26 and Massena at 21 as of 1 AM. As the boundary continues southeastward early this morning, shallow moisture will be dragged along with it as brief ridging builds in for today. Most areas should see some sun this morning before clouds return this afternoon. Winds will also weaken to near calm by midday with a wind shift to the south taking place over the course of the day. Temperatures remain on the cool side in the 20s for most of the day before southerly winds and waa kicks in with temperatures reaching their highs Saturday evening, and will continue to increase into Saturday night.

A clipper system will ride north of the border, with a trend that has taken the system further north, resulting in stronger waa. Temperatures by Saturday evening should reach back to freezing and perhaps into the mid 30s for the Champlain and St. Lawrence Valleys overnight. These warmer temperatures will be ushered in by a strong 60-70 kt jet at 5000ft agl. Given the northerly trend of the center of the low well north of the international border, precipitation chances have lowered with mainly just chances near the international border and in the Adirondacks. While precipitation should start as snow for most areas Saturday evening, rain will mix in across the St. Lawrence Valley overnight. With the center of the low to the north, chances of impacts from the associated cold front will increase. The NAM soundings suggest the presence of about 100-150 J/kg of CAPE associated with the boundary over northern New York with decent convergence along a thin area of frontogenesis. By Sunday morning there is a increased chance of some heavier bands of showers, with embedded snow squalls possible which could impact travel Sunday morning, particularly in the St. Lawrence Valley. Concurrently ahead of this boundary will be a weak lake effect band off Lake Ontario. While the flow regime will be favorable for banding across southern St. Lawrence County, temperature profiles will limit snow, and will likely be more rain under the band into Sunday morning with temperatures in the low to mid 30s.

With precipitation chances lowered, more mixing will take place with channeled flow in the wider valleys as the surface warms, but 850mb temperatures undergo caa leading up to sunrise Sunday morning. HREF probabilities suggest an 80% chance of seeing >40 mph gusts at BTV Saturday night. Also concerning is that there is good agreement in 40kt winds at 1000ft on GFS/NAM/HRRR soundings, which would not take much forcing to mix these winds to the surface. Consequently, have increased gusts, especially in the CPV Saturday night up to 30 to 35 mph, with future updates likely to increase further if trends continue. Temperatures will continue to be on the rise Saturday night into Sunday morning following a non-diurnal curve with little typical overnight cooling taking place. Temperatures by Sunday morning will be about 10 degrees warmer than the same time this morning.

SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/

As of 139 AM EST Saturday...A cold front will slowly pass through the region Sunday morning from west to east. The band will lose most of the forcing associated with it as the parent system lifts north further away from the area, drawing most of the energy and moisture with it. Main concerns will be continued gusty winds during the day Sunday across the northern Adirondacks and Champlain Valley with gusts 25 to 35 mph. Lake effect showers will wain with the passage of the boundary shifting winds and the axis of the band south of the region. Temperatures will fall back to single digits and low teens Sunday night with good caa. Wind chills will be near 0 to the negative single digits with gusts continuing. While moisture will be limited, northwest flow with orographic lift should keep some slight to chance PoPs across the western facing slopes of the northern Adirondacks and northern Greens Sunday night into the day Monday. Snow ratios will be 15-20:1 with any snow that falls on the more light and fluffy consistency. A few inches of snow is possible close to Jay Peak and in the Adirondacks. Temperatures will be relatively seasonable in the low to mid 20s with weaker winds Monday.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

As of 139 AM EST Saturday...A clipper system approaching from the central Great Lakes region will bring the potential for light snowfall across northern NY and VT, likely starting during the pre- dawn hours Tuesday across northern NY, with stratiform snow overspreading the remainder of Vermont through mid- morning. There is a low chance of a rain/snow mix during Tuesday afternoon as boundary layer temperatures warm into the 33-36F range in the immediate Champlain Valley and the St. Lawrence Valley. That said, snow should be the predominant precipitation type, with some minor travel impacts due to snow covered roadways expected throughout Tuesday. Based on present indications, a 2-4" snowfall is generally expected, with the bulk of that falling during the daylight hours on Tuesday.

Once the clipper system translates to our east, sfc high pressure will briefly crest over the North Country for Christmas Eve Day. Generally dry conditions expected with seasonable high temperatures in the mid-upper 20s, except lower 30s for the valleys of s-central Vermont. Once the sfc ridge axis shifts to our east, breezy S-SW low- level flow will redevelop across our region for Christmas Day. This will allow temperatures to warm into the 35-40F range for Christmas afternoon. Modest low-level warm advection may be sufficient to result in some light rain/snow showers on Christmas, but overall forcing appears weak at the present time. Indicated 30-50% PoPs for rain or snow showers, and slightly higher (60%) across the higher summits. Above normal temperatures will continue into Friday with highs near 40F in most locations.

AVIATION /07Z SATURDAY THROUGH WEDNESDAY/

Through 12Z Sunday...A cold front will bring periods of snow shower activity (1-3sm vsby) for a brief time between 06-09Z this morning with minimum snow accumulations expected (generally a coating to 0.5"). Temperatures will be dropping below freezing with the frontal passage, which may result in icy spots for airport ground operations across the region. Diminishing clouds expected through the daylight period with VFR conditions returning to all TAF locations by 12Z Saturday. Surface winds will be quite changeable across VT and northern NY during the next 24 hours. Seeing W winds generally 10- 20kts and gusts up to 30kts thru the pre-dawn hours Saturday. Winds briefly shift into the NW and N during Saturday morning. Winds shift back into the S-SW quickly late Saturday afternoon and evening, with at BTV, expecting south winds 15-20kts with gusts to 30kts starting around 00Z Sunday. Will also be monitoring for LLWS areawide during the 00-12Z Sunday period as gradient flow becomes moderately strong.

Outlook...

Sunday: VFR. Chance SN, Chance SHSN. Sunday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Monday: VFR. NO SIG WX. Monday Night: Mainly VFR, with local MVFR possible. Chance SHSN. Tuesday: Mainly MVFR and IFR, with areas VFR possible. Definite SHSN. Tuesday Night: Mainly MVFR, with local IFR possible. Chance SHSN. Wednesday: Mainly VFR, with areas MVFR possible. NO SIG WX.

MARINE

A Lake Wind Advisory continues tonight for gusty west winds of 15 to 25 knots with localized gusts 25 to 30 knots possible. Waves will be 2 to 5 feet on the board lake. Winds quickly decrease toward sunrise on Saturday, before increasing again on Saturday night.

EQUIPMENT

NOAA Weather Radio station WXM-44, transmitting from Mt. Ascutney, Vermont, on frequency 162.475 MHz is non-operational at this time. NWS technicians have diagnosed the problem, but repairs will likely not be able to occur for quite some time due to circumstances beyond our control. Therefore, the time of return to service is currently unknown. The following NOAA Weather Radio transmitters may be able to provide service during this outage: WWG 50 from Burke Mtn, VT at 162.425 MHz and WNG 546 from Hanover, NH at 162.525 MHz.

Equipment malfunctions at the Colchester Reef meteorological station will likely leave it inoperable for an extended period of time. This site is not serviced by the NWS. Technicians do not currently have an estimated return to service for this station. Use extra caution when navigating the broad waters of Lake Champlain, and please contact us if you observe winds significantly deviating from the forecast.

BTV WATCHES/WARNINGS/ADVISORIES

VT...Wind Advisory until 7 AM EST this morning for VTZ003-004- 006>008-010-019>021. NY...Wind Advisory until 7 AM EST this morning for NYZ026>031-034- 035.