textproduct: Burlington

WHAT HAS CHANGED

As of 237 AM EDT Sunday...

Freezing drizzle is looking increasingly likely late tonight into Monday morning. Total ice accumulations between a glaze and 0.05 inches is now expected; mainly across Vermont.

KEY MESSAGES

As of 237 AM EDT Sunday...

1. A clipper will move across the North Country and northern New York tonight into Monday morning bringing widespread snowfall and a change to a rain/snow mix across southern Vermont and the St. Lawrence and Champlain Valleys tomorrow afternoon.

2. Seasonally cool and drier to start next week.

3. Multiple weather disturbances expected for Vermont and Northern New York for the back end of the week.

DISCUSSION

As of 237 AM EDT Sunday...

KEY MESSAGE 1: A Winter Weather Advisory remains in effect from 8 PM this evening through 8 AM Monday morning for the Adirondack region in New York and the spine of the Green Mountains eastward in Vermont for 3 to 6 inches of snow and a light glaze of ice. Zonal flow will begin to break down this evening as a weak surface low moves across the Great Lakes Region this afternoon. The surface low is currently meandering across the upper Midwest with mid to high level clouds advecting into the region from the northwest. Precipitation will begin as widespread snow from west to east beginning in northern New York by 8 PM and arriving in Vermont by Midnight tonight. Models have mainly stabilized on the low center track across southern Vermont and along the southern Adirondacks. This favors more snow across the North Country and areas north of US-4 initially. HREF mean snow rates show 0.5-0.75 inch/hr rates which is supported by a shallow DGZ thicknesses between 3-5kft at 12,000ft on HRRR model soundings. As the system progress eastward tonight, 850mb frontogenesis will increase between 1 AM and 10 AM when the highest snowfall amounts are expected. Snowfall amounts will vary from 1-3" across the St. Lawrence and Champlain Valley, with possibly 6 to 10 inches across the upslope favored summits in the western slopes of the Green Mountains. The snow will be of a wet character with snow ratios favoring ratios from 7-10:1, with lower ratios across southern Vermont.

Beyond 10 AM, a dry slot may entrain some dry air into the Champlain Valley and portions of southern Vermont which will lead to a drying of the mid to upper levels, and thus a loss of cloud ice in the DGZ. This dry slot will also be accompanied by temperatures in the 32-36 degree range which will could lead to some mixed precipitation in the form of snow and rain in a narrow band from Newcomb, NY to Middlebury and White River Junction in Vermont. Furthermore, as we lose cloud ice tomorrow afternoon, and moisture lingers at the surface, precipitation may trend towards drizzle and freezing drizzle in the Champlain Valley and southern Vermont. Within this mixed precipitation and potential freezing drizzle, up to a light glaze of ice is possible. Portions of southern Rutland and Windsor counties may remain completely rain through the event. Any freezing precipitation will be short lived, as the DGZ will sink closer to the surface back into the shallow moisture by tomorrow evening. As with last night, some patchy freezing fog may develop in the low lying areas Sunday night, but confidence is low so it was not included in the current forecast. Main impacts from this event will include hazardous travel beginning tonight through the Monday morning commute from slick roads.

KEY MESSAGE 2: Following the clipper system, a 1030mb area of high pressure will build into the region for Monday night into Tuesday. Low to mid level moisture will dry out as subsidence from the high and drier southerly air will entrain into the area. Skies should become mainly sunny to mostly sunny, especially over the St. Lawrence on Tuesday. Clouds may linger across eastern Vermont with a weak trough hanging on in the wake of our clipper system Sunday. Temperatures under the high will generally be seasonable to 5 degrees below normal, particularly in northern New York and eastern Vermont, as we will still be under the influence of a dominating upper level trough, which is fairly normal for late March.

KEY MESSAGE 3: A cold front pushes through Wednesday morning, bringing some snow showers, with the best chances along the western slopes where orographic lift can help the lack of forcing and moisture. There's still some question on how far south the cold air moves into the region, with highs in the low 30s across the northern half of the CWA and in the upper 30s to 40s across the southern counties.

Models are still split on the next system that could move through early on Thursday, with low tracks to the north and south of the region, bringing some chances for early snow showers.

Models do have better agreement for the system directly behind, that moves in late Thursday night and into Friday morning that brings a general rain-snow mix to the area that will bare watching. Behind this system we could see a brief unseasonable cool down Friday night with overnight lows in the teens to single digits before becoming more seasonal next weekend.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Through 06Z Monday...Snow is moving through the St Lawrence Valley and into the Dacks. Expect IFR vis in light snow to develop at SLK/MSS around 06Z and after 08z for other stations. Cigs lower from VFR to MVFR conditions as snow develops with IFR visibilities prevailing at most sites thru 12z. As warmer surface temps develop, expect some mix with rain with MVFR vis developing in our valley taf sites by 14z Sunday. Precip should exit our taf sites by 18z, with lingering areas of drizzle/freezing drizzle developing, along with lowering ceiling back toward IFR and possibly LIFR at a few locations, especially Champlain Valley with developing northwest winds after 21z. This wind direction combined with strongly blocked flow, will result in a long duration of IFR cigs at RUT/BTV thru Sunday night, with additional IFR cigs likely at SLK/MPV and EFK. Some localized low level wind shear is likely through the early morning hours.

Outlook...

Monday: Mainly MVFR, with areas VFR possible. Chance SN, Chance FZDZ. Monday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Slight chance SN. Wednesday: VFR. Chance SN, Chance RA. Wednesday Night: Mainly VFR, with local MVFR possible. Chance SN, Chance RA. Thursday: Mainly MVFR, with areas VFR possible. Chance RA, Chance SN.

EQUIPMENT

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...Winter Weather Advisory until 8 AM EDT Monday for VTZ003-004- 006>008-010-017>021. NY...Winter Weather Advisory until 8 AM EDT Monday for NYZ027-030- 031-034.