textproduct: Burlington

WHAT HAS CHANGED

As of 703 AM EST Wednesday...Quick update to place patchy fog into the forecast, as OGS is at 1/2SM and Middlebury is 1/4SM, also drove thru several areas of dense fog while coming to work this morning on Interstate 89. Please drive carefully this morning.

KEY MESSAGES

As of 136 AM EST Wednesday...

1. Mostly dry and seasonable conditions will prevail across the region, with an area of low pressure bringing light snow across southern Vermont this evening.

2. Increasing confidence on snow Friday afternoon into Saturday that will impact the Friday evening commute with a 60-70 percent chance of at least 4 inches across the Adirondacks of New York east into Vermont.

DISCUSSION

As of 136 AM EST Wednesday...

KEY MESSAGE 1: A mostly dry and seasonable day is expected across the region today as a frontal boundary stalls to our south and an area of low pressure tracks along this feature. Temperatures will be rather seasonable across the region today, with highs generally in the upper 20s to mid 30s. The axis of heaviest precipitation looks to remain to our south, with only some light snowfall expected across Rutland and Windsor Counties with more snow expected across far southern Vermont. The timing of precipitation in these areas will be during the evening commute, with slick travel conditions possible in any locations that receive snow, but luckily the trend of decreasing snow amounts will limit any impacts. As the previous forecast mentioned, consensus continues to support the bulk of the precipitation remaining to our south, with some deterministic guidance showing no precipitation across southern Vermont at all. Precipitation chances will taper off tomorrow night, with drier conditions prevailing and cooler overnight temperatures, with lows dropping back into the teens. A rather quiet day is expected for Thursday as high pressure builds into the region.

KEY MESSAGE 2: Forecast guidance is coming into better alignment with respect to the start time of precipitation on Friday and the evolution of the system on Saturday. The overall pattern features blocked low pressure still going around the Great Lakes region with a new surface low developing from the south, and eventually taking over. As it matures over the Great Lakes, a triple point low may try to develop over Lake Ontario. This will send a modest warm front with excellent upper divergence and enhanced deformation as a result of another upper low in the Canadian maritimes. Once the better upper forcing departs, the boundary will begin to decay. A coastal low will begin to pull away better forcing. A backdoor cold front will likely cause the warm front to stall out, and even as the decaying surface low from the Great Lakes begins to become increasingly elongated, it should still supply enough low-level convergence with adequate moisture to maintain light snow into Saturday.

So this event will feature a quick burst of moderate to heavy snow Friday afternoon, which will likely impact the Friday evening commute for parts of the area, and then it will trend towards a steady light snow through Saturday when a backdoor cold front begins to shift the boundary away from us. Depending on how far north the warm front gets, we may see a warm nose nudge into parts of the forecast area, and a mix is possible in the St. Lawrence Valley and parts of the Champlain Valley. Additionally, surface temperatures may be marginal Friday afternoon and evening, which may limit accumulations where temperatures are above freezing with lighter snow. The most favorable areas will be where easterly flow enhances upslope and locks in colder air for eastern Vermont and eastern slopes of the Adirondacks. Probabilities of 8" between both days are about 20-40%. Mesoscale guidance will be important to the intricacies of this system. So stay tuned. Temperatures will be seasonable beyond Saturday, with continued snow showers possible. Although with another strong coastal possible south of the 40 N 70 W benchmark, some dry air may filter early next week.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Through 12Z Thursday...Lingering MVFR stratus and intermittent fog is being observed. A cold front continues to move south, but has been a little slower to shift south than expected. Clearing is being observed behind it, and there has been patchy fog within the clearing. With the sun rising, steady improvements are expected, and by 14z, sites will become all VFR. Northwest to north winds of 5-10 knots are expected beyond 14z, which will decrease after 22-23z. Mid to high clouds will be prevalent much of the next 24 hours, and snow will remain south of the region. VFR conditions are expected to continue beyond 06z Thursday.

Outlook...

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