textproduct: Burlington

WHAT HAS CHANGED

As of 158 PM EST Wednesday...No significant changes have been made.

KEY MESSAGES

As of 158 PM EST Wednesday...

1. Following an extended dry period, widespread snow is expected to end the week. A burst of heavier snow could impact the Friday evening commute, followed by some lighter snow lingering into Saturday.

2. Quiet seasonable weather early next week.

DISCUSSION

As of 158 PM EST Wednesday...

KEY MESSAGE 1: Low level dry air has returned to the area which will be largely constant through Friday morning, supported by an upper ridge axis remaining near and just west of our region, and will lead to seasonably cold conditions especially at night. An area of surface high pressure will push to our east on Friday while polar high pressure to our north holds in place while warm air advection supports widespread precipitation in a classic overrunning scenario. As the primarily low pressure system to our west weakens as it passes overhead, the associated trough will be slow to pass through and help maintain some light snow into Saturday. Event total snowfall has ticked up a little bit with the latest forecast with perhaps a better signal for additional snowfall on Saturday than previously indicated. As the event begins, model guidance overwhelmingly shows mainly snow as the precipitation type for most areas, with the exception of early in the event perhaps enough east/southeasterly flow to have some rain in portions of southeastern St. Lawrence County as well as some brief wintry mix in southern portions of Vermont.

There is very good consensus on a thump of heavy snowfall rates, which will would be in the 1-2"/hour range for a short period of time as the strongest mid-level frontogenesis translates northeastward through our region. The heaviest precipitation rates may be over northeastern New York, but not necessarily especially more impactful than the snow farther east depending on timing. Unfortunately the most likely timeframe of the heavier snowfall will coincide with the evening commute, so please plan accordingly if traveling. Snow to liquid ratios will tend to be on the wet side although there are somewhat mixed signals on the consistency of the snow related to thermal profiles. Generally expect ratios could be near 10:1, especially where near surface temperatures begin near freezing, and trend a drier Friday night. Would note that QPF/snow amounts in this time range are a little smoothed out to account for model differences, such that one should not take any 6 hourly snowfall amounts verbatim. The event total snowfall, currently in the 4 to 7 inch range for most locations, should be somewhat more predictable. Yet, as for all winter storms, expect some surprises as we fine tune the forecast. Right now, forecaster concerns include the degree of low level drying on the northeast flank of the system eating away at precipitation rates, potential for more terrain- shadowing/upslope snow if 925-850 millibar flow is stronger with a deeper primarily low to our west, and more mixed precipitation early in the event.

KEY MESSAGE 2: A nor'easter is expected to miss the region well to the southeast Sunday into Monday, keeping any significant snow well to the south. Its only effects would be slightly enhanced winds and increased clouds. A separate shortwave will try to move into the region from the Great Lakes on Sunday but at most it would bring a few light snow showers. These could linger into Monday but any accumulation would be very light. The next more impactful storm looks to arrive in the Wednesday-Thursday timeframe. A low looks to track by to the west and up the St. Lawrence Valley, but warm-air advection should be limited ahead of it so much of the precipitation still looks to fall as snow.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Through 00Z Friday...Conditions will remain VFR through the entire period as primary weather producer will stay south of Vermont and the Adirondacks. Dense cirrus will linger 06-12Z before drier air aloft presses southward eroding the edge of the cloud shield. Winds will generally be northerly through the period outside of upslope/downslope patterns overnight.

Outlook...

Thursday Night: VFR. NO SIG WX. Friday: Mainly VFR, with areas MVFR possible. Chance SN, Chance RA. Friday Night: Mainly MVFR, with local IFR possible. Definite SN. Saturday: Mainly MVFR, with local VFR possible. Chance SN. Saturday Night: Mainly VFR, with local MVFR possible. Slight chance SN. Sunday: Mainly VFR, with local MVFR possible. NO SIG WX. Sunday Night: VFR. Slight chance SN. Monday: VFR. Slight chance SN.

EQUIPMENT

The KMPV ASOS has suffered a communications failure. The issue has been diagnosed, but there is currently no estimated time of return to service. Terminal Aerodrome Forecasts will continue, but amendments to those forecasts will be suspended.

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. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

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