textproduct: Burlington

KEY MESSAGES

As of 151 AM EST Monday...

1. Lake effect snow will impact southern St Lawrence county today through Tuesday. Snow squalls will also be possible Monday evening, especially across northern New York. Outside of snow squalls, winds will remain gusty with periods of low visibility expected.

2. An arctic airmass is expected to bring dangerously cold temperatures to the region this weekend.

3. Snow showers and possible snow squalls may lead to hazardous travel conditions at times, especially on Thursday.

DISCUSSION

As of 151 AM EST Monday...

.KEY MESSAGE 1: Lake effect showers are beginning to ramp up with more scattered showers becoming consolidated into a rough band off the northeast end of Lake Ontario. These showers are just extending into southern St Lawrence County as seen on radar imagery. Shear aloft will keep these showers from becoming a consolidated band through this afternoon. Additionally, there will be a prefrontal trough passing through northern New York this afternoon supporting snow squalls as the wind field increases. Gusty generally will range 20-35 mph with up to 40 mph during squalls - whiteout conditions will be possible this afternoon and evening. Some CAMs are showing potential for convective showers tracking farther eastward into Vermont, but it remains to be seen if these will be actualized. Should these occur, bursts of snow and low visibility will be a concern. The threat period for convective showers in northern New York and potentially portions of Vermont will be between 2PM and 11 PM.

The expectation remains that a lake effect band will become consolidated as flow goes unidirectional late this evening and waver across southern St Lawrence County bringing 3 to 6 inches in general with localized higher amounts possible. One change was to increase snow ratios through tonight as temperatures fall resulting in a fluffier character of snow; it's feasible to see periods of 25+:1 ratios tonight suggesting potential for localized totals to approach 8 inches. With high ratios coupled with increasing winds as deep low pressure tracks northwest of the St Lawrence Valley, periods of low very low visibility will be assured especially southeast of Highway 11 and Gouverneur in southeastern St Lawrence County.

.KEY MESSAGE 2: An extremely cold airmass will move into the region late this week into the weekend, bringing dangerously cold temperatures and wind chills. Frigid conditions are expected Friday, with the current forecasting showing highs in the teens and single digits, with the much colder air expected to arrive towards the weekend. The current NBM forecast has daytime high temperatures only climbing into the single digits above and below zero during the day Saturday, with overnight lows well below zero areawide, with portions of the Adirondacks possible dropping to -20F overnight. Northwesterly flow will make for even colder apparent temperatures. While there will likely be some changes in the exact magnitude of the cold and winds, the cold this weekend will be dangerous with Cold Weather Advisories and/or Extreme Cold Warnings likely needed as we get closer.

.KEY MESSAGE 3: A clipper system will push across the region Wednesday night into Thursday, bringing some widespread chances for snowfall. Northern New York will likely see the highest snowfall accumulations due to enhancement off Lake Ontario, with the NBM current showing a 25 to 50 percent chance of 2 or more inches while Vermont will likely only see a dusting to a inch in most locations. As the low continues to move eastward, an arctic boundary associated with the system looks to push across the region during the day on Thursday, which may allow for some heavier snow showers and possible snow squalls. There is still some uncertainty in the exact timing of the system and just how dynamic the front will be, but it currently looks to be favorable for these heavier showers, making for some slick and potentially hazardous travel on Thursday, so be sure to stay tuned as we get closer. Beyond Thursday, flow aloft looks to become more zonal with surface high pressure building into the region so while there may be additional chances for precipitation, it looks to be quite showery and organized at this time.

AVIATION /18Z MONDAY THROUGH SATURDAY/

Through 18Z Tuesday...Aviation challenge is timing of intervals of IFR/LIFR snow showers and embedded snow squalls through this evening. Currently a mix of IFR at SLK to VFR elsewhere with radar imagery showing scattered snow shower activity increasing in areal coverage. The highest probability of frequent IFR conditions or lower will be at SLK/MSS through 00z this evening with 30% to 50% probability at EFK/MPV and 20-30% at PBG/BTV and RUT. Have utilized a combination of PROB30 and TEMPO groups to highlight periods/intervals of IFR conditions thru this evening. Also, brisk south to southwest winds 15 to 25 knots will create some areas of blowing/drifting snow, along with some reduced sfc vis. Conditions improve to VFR with MVFR cigs in the mountains by midnight with mostly VFR by sunrise on Tuesday. Winds shift to the west/northwest by Tues morning.

Outlook...

Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. Chance SN. Wednesday Night: Mainly VFR, with local MVFR possible. Chance SN. Thursday: Mainly VFR, with local MVFR possible. Chance SHSN. Thursday Night: VFR. Slight chance SHSN. Friday: VFR. Slight chance SHSN. Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Saturday: VFR. NO SIG WX.

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...Winter Weather Advisory until 1 PM EST Tuesday for NYZ029-087.