textproduct: Burlington

WHAT HAS CHANGED

As of 255 PM EDT Saturday...

No major changes were made to the overall forecast. A light glaze of ice was added to portions of the Adirondacks and eastern Vermont for tomorrow afternoon.

KEY MESSAGES

As of 255 PM EDT Saturday...

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. Several weather disturbances are projected to traverse Vermont and northern New York for the rest of the week.

DISCUSSION

As of 255 PM EDT Saturday...

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: Tuesday night into Wednesday will begin with a reinforcing cold front impacting the region. Surface low pressure will be well north with a tenuous strand of moisture. Scattered snow showers will occur overnight into early Wednesday morning, mainly for favored western slopes where orographic lift can help the lack of forcing and moisture. Wednesday itself should be cool and somewhat breezy as a 1032mb surface high builds across Quebec Province.

Active channeled flow across the region will bring the next system in Wednesday night into Thursday morning. Forecast scenarios are split on the low position and the orientation of track. One cluster has low pressure ejecting northeast with a surge of warm air on Thursday. Other clusters depict the low tracking west to east with a mix of rain and snow depending on elevation with cooler conditions overall. With ensembles in a roughly 50-50 split, it seems unwise to commit to any particular solution. The pattern split continues down- forecast. Cooler than normal temperatures are present across either end of diverging model guidance, but the end of next week could either be dry, or it could have another round of light snow showers.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

Through 00Z Monday...Current radar shows light snow quickly angling toward the St Lawrence River Valley this evening, but surface dwpts in the 20s has resulted in precip not reaching the ground. Expect IFR vis in light snow to develop at SLK/MSS between 2-4Z and 4-6Z for PBG/RUT/BTV and after 06z for MPV/EFK. 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, 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 after midnight tonight.

Outlook...

Sunday Night: MVFR/IFR conditions possible. Chance SN, Slight chance FZDZ. Monday: Mainly MVFR, with areas VFR possible. Chance SN. Monday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Chance SN. Wednesday: Mainly VFR, with areas MVFR possible. Chance SHSN, Chance SHRA. Wednesday Night: Mainly VFR, with local MVFR possible. Chance SHSN. Thursday: Mainly MVFR, with areas VFR possible. Chance SHRA, Chance SHSN.

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.