textproduct: Burlington

SYNOPSIS

A few light snow showers will continue this afternoon and evening with minimal impacts. A clipper system will bring steady light snow starting during the day on Tuesday, and continuing into Tuesday night and early Wednesday. Several inches of snow accumulation will likely bring at least some minor travel impacts. Quieter conditions are expected for Christmas Eve and Christmas Day, though a few mountain snow showers will continue to be possible.

NEAR TERM /THROUGH TONIGHT/

As of 652 PM EST Monday...Updated the forecast to show high probabilities of light snow across much of northern Vermont and northeastern New York where a large area of steady, accumulating snow has blossomed. A fresh coating to locally 2 inches of snowfall can be expected when it tapers off over the next couple of hours. Mesoscale analysis shows best low level warm air advection at 925 and 850 millibars overhead and it will be shifting to the east consistent with radar trends, as moisture becomes too shallow to support snow growth while weak lift lingers.

Previous Discussion...A few light showers have gradually been pushing east and expanding in coverage today. Limited moisture and weak forcing will keep rates low, but relatively long duration could allow a few areas to reach close to an inch. Very dry low levels will cause some sublimation, but it will not be enough to stop the snow from reaching the ground. Temperatures in the teens and twenties will cause no trouble for this snow to accumulate, despite the very low rates. This initial warm air advection snow will dissipate this evening and conditions tonight will be mostly dry. Return southerly flow will develop tonight and continue into tomorrow, but it will be much less strong than with the previous couple systems.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

As of 136 PM EST Monday...A more impactful but still relatively weak clipper moves through tomorrow and tomorrow night. Overall, models have converged on a general solution and confidence has increased on the impacts. A weak surface low will track far to the north close to James Bay and then quickly dive southeast as it runs into a nearly stationary ridge situated over Atlantic Canada. There will be modest overrunning along a narrow axis extending well southeast of the low that will very gradually push northeast. Right now, the consensus is that light snow will enter southwestern areas in the morning and northeastern areas in the afternoon, before eventually pushing to the east overnight. The relatively long residence time of the snow, despite relatively low rates, will allow for most areas to see a few inches. Right now, it looks like the Champlain, St. Lawrence and lower Connecticut River valleys should see between 2 to 4 inches, while everywhere else sees 3-5. Locally higher totals will occur in the mountains. As the moisture becomes more shallow across northern New York Tuesday evening, the snow growth zone may lose moisture. This could lead to patchy freezing drizzle, but that looks unlikely as right now there should just be enough cloud ice. The snow growth zone will also be lowering into the remaining moisture as it retreats into lower levels. Upslope snow will continue on the backside into Wednesday, where an additional couple inches are possible in the mountains. Winds will increase Tuesday night as the cold front comes through and causes mixing in a cold air advection profile, but a weaker jet should cause gusts to only be in the 20 to 30 mph range.

LONG TERM /THURSDAY THROUGH MONDAY/

As of 1257 PM EST Monday...Some light snow is expected for Christmas day as an upper level shortwave and weak surface low crosses along the international border. Best chance for snow showers will be along the spine of the northern Green mountains. At this point only expecting a couple of inches of snow at most. Snow showers will wind down Thursday night. We will have a brief break in precipitation for the daytime hours on Friday. Next system approaches our area for Friday night as a low pressure passes south of our region from the Ohio river valley eastward. There has not been a lot of model to model or run to run consistency with this feature yet, but will have a better idea as we get closer to the end of the week. For now have light snow in the forecast. Weather looks drier and quieter on Saturday, then another system will cross our region from northwest to southeast with precipitation spreading into our area Saturday night into Sunday. Temperatures will warm above freezing on Sunday, therefore may have rain or mixed precipitation to contend with. At this time we are much too far out to get overly detailed with precipitation type, but this will be something that we're watching. Upper trough will remain over our region as this low exits to the southeast, therefore snow showers will carry us into the beginning of next week.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Through 00z Tuesday...Warm air advection light, low density snow with visibilities mainly between 1 and 2 statute miles has blossomed over much of the airspace east of MSS and north of RUT. This activity should be short-lived, gradually tapering off and shifting eastward over the next 1 to 4 hours. As such, conditions will improve tonight with a mix of VFR and MVFR ceilings.

A larger area of widespread light to moderate snow is still on track to overspread the area during the day Tuesday, roughly from 15Z to 19Z, with steady IFR conditions expected through the remainder of the period following onset of snow. Character of snow is expected to be on the wetter side of average, roughly 11 or 12 to 1 snow-liquid ratios. Surface winds will tend to be light and southerly, except at MSS where light (under 10 knots) north to northeast winds are more likely.

Outlook...

Tuesday Night: MVFR/IFR conditions possible. Definite SN. Wednesday: Mainly VFR, with areas MVFR possible. Chance SN. Wednesday Night: Mainly VFR, with local MVFR possible. Chance SHSN. Christmas Day: MVFR. Slight chance SN. Thursday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Friday: VFR. Chance SN. Friday Night: VFR. Chance SN. Saturday: Mainly VFR, with areas MVFR possible. Chance SN, Chance SHSN.

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.

The temperature sensor at Massena ASOS/Richards Field has been reading too high. Technicians have plans to visit the site to diagnose the issue in the next couple days.

BTV WATCHES/WARNINGS/ADVISORIES

VT...Winter Weather Advisory from 7 AM Tuesday to 7 AM EST Wednesday for VTZ003-004-006>008-010-016>020. NY...Winter Weather Advisory from 7 AM Tuesday to 7 AM EST Wednesday for NYZ029>031-034.