textproduct: Burlington

SYNOPSIS

Snow showers are starting to move into the area this morning. The terrain driven nature of this system will lead to accumulations of several inches in the northern Greens and Adirondacks. Friday will be sharply colder following a frontal passage, min temperatures will fall into the single digits above and below zero in the morning. The next impactful system will arrive on Monday with the potential for mixed precipitation.

NEAR TERM /THROUGH TONIGHT/

As of 809 AM EST Thursday...Issued a quick update this morning, mainly to freshen up PoPs and weather to match the latest radar trends. The steadiest snow is pushing southward through northern VT and NY at this hour, associated with a cold frontal boundary moving out of Canada. Snow will taper to scattered showers from north to south as this feature moves through. Winds will turn to the N/NW and become gusty behind the front as well, which may lead to areas of blowing snow. Snow accumulation will be light, mainly less than 2 inches, though more is expected on the higher summits. Even a bit of snow accumulation can make for slippery roads, so please use caution if you'll be out and about today.

Previous discussion...Radar shows snow approaching northern New York and Vermont from the north. The primary push of snow should be through the area by 15z, bringing an inch or two to many locations. CAMS are suggesting some the northern Greens might hold on to some orographic snow through the early afternoon hours. We could also see some light lake enhanced snow this afternoon and into the overnight hours south of Lake Champlain. Following the snow, an arctic cold front will sweep into the area dropping temperatures below zero for much of our forecast area. Southern Vermont will be the warmest location in our forecast area but is still showing a 20% chance of falling below zero.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/

As of 205 AM EST Thursday...The arctic air will remain in place during the day Friday, with temperatures only warming into the teens for most locations, with single digits remaining in colder and higher elevation areas. Friday night into Saturday a low pressure system will dive south of our CWA. Model guidance has routinely showed this system delivering a glancing blow to us, with some light snowfall in southern Vermont and the Southern Adirondacks, with the rest of our area only seeing some flurries. The NAM3 is now diverging from that consensus, with a low passage far enough north tn on to bring more substantial snowfall to Vermont and northern New York. We will continue to monitor the high res models as they hone in on this system.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

As of 205 AM EST Thursday...We remain on track to see a classic setup for transient, freezing rain as an intensifying low pressure system tracks to our west with a retreating, cool high pressure system to our east. While we maintained mention of snow with some inherent precipitation type questions in this time range (eg. some global ensemble members suggest snow is possible), there really is a strong consensus of mainly freezing rain/rain scenario Sunday night into Monday until the low pressure system passes to our northeast and winds shift westerly. Expect Winter Weather Advisories could be needed areawide for Sunday night/early Monday with at least light freezing rain given cold surface conditions and only a light 925/surface south to southeast wind through this period. Preliminary thoughts for ice amounts in the range of 0.1" to 0.25" of flat ice, and locally 0.5", seems reasonable for most of the region at this time, with maybe a trace of ice in some areas that warm above freezing relatively quickly in these scenario with southeasterly low level wind, such as in southeastern St. Lawrence County.

The other potential hazards with this event would be related to gusty winds and falling temperatures on the backside of the storm. The ECMWF Extreme Forecast Index supports noteworthy, if not particularly unusual, westerly wind gusts later Monday into Tuesday. As we get closer to this period we'll also target lake- effect/terrain-driven heavier snow potential, and generally fine- tune coverage of snow showers. Broad cyclonic flow and seasonably cold air will set up multiple opportunities for snow in our region on Tuesday and Wednesday.

AVIATION /13Z THURSDAY THROUGH MONDAY/

Through 12Z Friday...It remains a somewhat difficult forecast for northern portions of the airspace with regards to operational impacts early in the period ahead of an approaching cold front. Following a brief respite of steady snow, another batch of snow near the International Border at 12Z, on the leading edge of the front, will move southward bringing at least temporary IFR conditions to most terminals through 15Z. Aside from the snow, MVFR conditions are expected through the rest of the period driven by ceilings. A shallow, post-frontal stratus layer is expected for much of the period, with scattering first at MSS and much later at other sites, based on model guidance and upstream observations with cloud bases mainly in the 1000-2000 foot range.

Light south/southwest winds are currently in place, as well as probable wind shear conditions at MPV/SLK/EFK/RUT. As the cold front passes we will see primarily northwest winds of 5-10 knots by 16Z with lack of LLWS. Winds will become gusty with 20-25 knots common, only diminishing slightly at most sites after 06Z.

Outlook...

Friday: VFR. NO SIG WX. Friday Night: VFR. Chance SN. Saturday: VFR. Slight chance SN. Saturday Night: VFR. NO SIG WX. Sunday: VFR. Chance SN, Slight chance FZRA. Sunday Night: Mainly VFR, with local MVFR possible. Definite PL, Chance FZRA, Chance SN. Monday: Mainly IFR, with areas MVFR possible. Windy with gusts to 30 kt. Definite SN, Definite RA, Definite FZRA, Definite PL.

MARINE

Behind a cold front, increasingly deep mixing of colder air will result in a long duration of strong northwest winds across the lake with 20-25 knot winds and gusts to 30 knots common late this morning and into the night. Maximum wave height of 3 to 6 feet over the broad waters and 2 to 4 feet in on the inland sea can be expected.

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.

The Colchester Reef meteorological station is out of service. This site is not serviced by the NWS and there isn't an estimated return to service at present. Use extra caution when navigating the broad waters of Lake Champlain. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

VT...None. NY...None.