textproduct: Burlington

WHAT HAS CHANGED

As of 153 AM EST Monday...

Snowfall amounts have decreased across the region, so the Winter Weather Advisory has been cancelled.

KEY MESSAGES

As of 624 AM EST Monday...

1. A strong nor'easter will bring snowfall and breezy conditions to the region, with the greatest snowfall amounts expected across southern and central Vermont.

2. Cold weather is expected Monday night through Tuesday night. With the combination of lingering strong northwest gusts, wind chills of -5 to -15 are possible over northern New York through Tuesday afternoon.

3. A clipper type system is expected early Wednesday into early Thursday. Snow will be possible during Wednesday's commutes.

4. Inland runner system track appears to be clustering southwards. Precipitation chances are starting to decrease over our northern tier.

DISCUSSION

As of 153 AM EST Monday...

KEY MESSAGE 1: The ongoing Nor'easter continues to bring heavy snow and blizzard conditions to southern New England, while our region remains on the northern periphery of the system. Compared to the previous forecasts, snowfall amounts have decreased with a tighter snowfall gradient, with about 2 to 4 inches of snow expected across south central Vermont, with increasing snow totals as you head towards the Massachusetts border. Given the lower snowfall amounts, the Winter Weather Advisory has been cancelled. As of now, the bulk of the snowfall looks to fall this morning, before gradually winding down this afternoon and evening as the coastal low pulls away. In addition to the snowfall, gusty winds are also expected with this system, with gusts in the 25 to 35 mph range increasingly likely across southern Vermont, peaking around the early afternoon with even higher gusts possible in the higher terrain. These winds could lead to blowing snow, making for hazardous travel conditions and reduced visibilities, especially in any mountain passes, so be sure be alert and use caution if traveling through central and southern Vermont on Monday.

KEY MESSAGE 2: As the coastal low pulls northeastward towards the Canadian Maritimes, cold conditions will move into the region. Overnight low temperatures look to drop into the single digits above and below zero across northern New York, while Vermont remains a but warmer in the single digits and teens. These cold temperatures combined with brisk northwesterly winds will make for wind chills in the -5 to -15 range across northern New York, with colder conditions possible at higher elevations. The Champlain Valley and rest of Vermont is likely to remain a bit warmer, as the core of coldest air doesn't arrive in Vermont until midday and will struggle to make it past the mountains. Highs on Tuesday will creep into the teens over northern New York and far northern Vermont, while the central/southern Champlain Valley and Upper Valley warm into the 20s. In addition to the cold temperatures, some additional light upslope snow showers will be possible night into Tuesday morning due to some wrap around moisture, but any accumulations look to be at this time. Temperatures Tuesday night will continue to be on the cold side, with forecast low temperatures in the single digits, however lighter winds and increasing cloud cover will play a role in actual temperatures overnight.

KEY MESSAGE 3: During the pre-dawn hours Tuesday night and Wednesday, a weak warm front will shift east across the area as a decaying clipper low tracks across the Canadian border and Great Lakes region. This is will bring light, powdery snow of a few tenths to maybe an inch. After that clears, we'll see our initially cool single digits start to climb. Shallow warm advection will warm most of the region into the upper 20s to mid 30s. However, above freezing air is confined to the lowest 500 feet of the atmosphere. In the "warm sector" of the clipper, marginally favorable low-level lapse rates of 7 C/km with the cool conditions aloft should result in roughly 100 J/kg of CAPE, Wednesday afternoon. A prefrontal trough will move across the region by evening. This should initiate some convective snow showers. Winds aloft are lacking, but a few embedded moderate snow showers may take place Wednesday evening due to marginal instability and the weak trough. After this round of activity, one last occluded boundary will shift east as the upper trough departs the region. Increasingly dry air will likely limit this last batch of snow to western slopes. All together, none of these round of precipitation will produce much snow. About 0.5-2.0", and 3-4" at mountain tops is the general expectation. This likely won't warrant headlines, but we'll monitor Wednesday evening activity for any possible travel impacts.

KEY MESSAGE 4: The system expected for Thursday night into Saturday is becoming less likely. A sizable number of ensembles and other guidance that originally had this feature are abandoning ship for a lower amplitude pattern that prevents the low from deepening substantially. Without a deep low, flow will be more zonal, and we won't tap into any moisture as the shortwave zooms east. The forecast still highlights a 30-50% chance of precipitation, but if trends continue, expect that number to decrease. Next on the docket, a powerful northern stream system will descend across central Canada on Saturday with the potential for a sharp push of warm air. Winter lovers need not fear, for as quickly as things heat up, we'll see cold air sweep southeast early next week.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Through 12Z Tuesday...Light snow is present across southern Vermont. Snow has reached KRUT at times, but visibility restrictions in snow has been limited. Some snow is possible through about 20z at KMPV or KRUT as strong coastal low ambles farther away, but the trend has been for less impact. So the main focus is LLWS, mainly across KRUT, KMPV, and KEFK as northeast to north winds of 35-40 knots at 2000 ft agl persist. While surface winds are strongest about 14z to 00z at 7 to 14 knots sustained with gusts 16 to 25 knots, LLWS will be more limited. After 06z, these winds aloft will begin to shift east, and surface winds will also subside. Light mountain snow is expected at KSLK about 00z to 07z as some low-level moisture shifts east. Blocked flow may allow some of these showers to reach favored northwestern foothills near KEFK or KBTV, with PROB30s noted. Ceilings will trend towards 2500-5000 ft agl after 00z.

Outlook...

Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Chance SN. Wednesday: Mainly MVFR and IFR, with areas VFR possible. Definite SN. Wednesday Night: Mainly VFR, with areas MVFR possible. Chance SN. Thursday: VFR. Slight chance SN. Thursday Night: VFR. Chance SN. Friday: Mainly MVFR, with local IFR possible. 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.