textproduct: Burlington

WHAT HAS CHANGED

As of 155 AM EST Tuesday...

No significant changes

KEY MESSAGES

As of 155 AM EST Tuesday...

1. Snow this evening and tonight.

2. Light Precipitation Thursday night into Friday

3. A period of light freezing rain is possible Friday night into Saturday, especially east of the Green Mtns, which could produce localized slick travel.

4. The potential for ice jams and hydro related issues will need to be monitored this weekend due to much above normal temperatures and significant snow melt.

DISCUSSION

As of 155 AM EST Tuesday...

KEY MESSAGE 1: A weak southern stream low passes through this afternoon and into tonight, bringing a round of light widespread precipitation. Despite no cold high to the north, there will be just enough lingering cold air for it to fall as mostly snow, though it will be on the wet side. While temperatures will be above freezing at the onset for many of the lower elevation areas, wet bulbing will cause the temperatures to drop and the precipitation to start as snow. The changeover line looks to stay over southern New England or far southern Vermont. There will be a good FGEN band on the onset that should cause briefly heavier rates but it will pass quickly to the east. Lots of dry air on the onset will cause virga but the precip will eventually saturate this layer. Overall, it will bring 1- 3 inches across central and southern areas and below an inch near the international border. After the steady precipitation moves out, some lingering low level moisture will cause the chance of freezing drizzle. However, this saturated layer only looks to be 1,000-2,000 feet deep so it is on the shallow side. Therefore, anything looks to be light and scattered and at most there would be a hundredth of two of an inch of ice accumulation. Most of this low-level moisture looks to scatter out late in the night and early Wednesday morning.

KEY MESSAGE 2: A weak system tracks northeastward through the region late Thursday night into Friday. It will be running directly into a cold high trying to build southeast out of Canada. Right now, the center of the high looks to be too far east to keep the system to the south, but close enough to provide enough surface cold air to cause some wintry precipitation. The current most likely scenario is that there is a notable warm nose Thursday night that causes the precipitation to start as a mix of rain and freezing rain. The warm nose looks to slowly erode during the event and it should eventually transition to more of a rain/snow mix by the end. This system will also be on the light side. The high begins to exit east on Friday and the cold air leaves with it for awhile.

KEY MESSAGE 3: WPC days 4 thru 7 weather grids indicate a period of light freezing rain is possible on Friday night into Saturday associated with initial surge of waa lift/moisture. WPC indicates temps in the mid 30s wider valleys, but upper 20s/lower 30s east of the Greens and portions of the northern SLV, supporting the threat for freezing rain. An advisory level event is possible, given marginal temps and modest qpf/ice accumulation expected. Strong llvl waa prevails on Saturday associated with progged 850mb jet of 50 to 60 knots from the southwest, which helps to advect 925mb temps btwn 7C and 10C. WPC's highs for Sat show values in the upper 40s to lower 50s, but if more mixing occurs with some breaks, several areas could approach 60F, especially southwest downslope areas of the northern and eastern Dacks, some slightly cooler air possible near the frozen Lake Champlain shoreline. Also, feel winds will need to be increased over WPC values, as their forecast shows 30 knots over Mt Marcy/Dacks and Greens on Saturday associated with a 50 to 60 knot jet at 4500 feet, which is too low. GFS did suggest some elevated instability upstream over the eastern Great Lakes on Saturday morning associated with the robust warm air advection profiles, which may produce a rumble or two of thunder. However, probability is too low attm to place in weather grids by WPC.

KEY MESSAGE 4: The latest WPC forecast for Sunday into early next week continues to show much above normal temps with highs in the mid 40s to mid 50s, while lows range hover either side of freezing. Given the duration of very warm temps, I anticipate much of the snow pack below 1500 feet will be gone by early next week, which combined with some intervals of precip wl cause rises on rivers and streams. These rises could be enough to produce localized ice jams and some hydro related issues. In addition, both the NAEFS and GEFS indicate Ausable, Mad, and Otter Creek have a 40 to 60% probability of reaching minor flood stage due to the combination of snow melt and qpf by early next week. We will continue to monitor the potential for both ice jam and main stem river flooding as we head toward the upcoming weekend. Some cooler air may try to impact our region at times by early next week per latest GFS solution, but latest forecast grids by WPC show temps upper 40s to mid 50s on Monday and Tuesday with lows in the upper 20s to mid 30s.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

Through 06Z Wednesday...High pressure will result in clear skies and light winds for the next 6 to 12 hours, before clouds thicken and lower toward 18z Tues. A band of light snow will overspread our central and southern TAF sites between 21z-03z this evening. Expect sharply falling vis to IFR with cigs trending toward mvfr by 00z. As low level moisture increases areas of IFR cigs will be possible toward 06z Weds. Wind become south/southeast with localized gusts up to 20 knots at BTV/RUT and mostly southwest at MSS, before becoming light again on Tues evening.

Outlook...

Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: Mainly MVFR, with local IFR possible. Chance RA, Chance SN. Friday: Mainly MVFR, with local IFR possible. Chance RA, Chance SN. Friday Night: Mainly MVFR, with local IFR possible. Chance RA. Saturday: Mainly MVFR, with local IFR possible. Likely RA.

EQUIPMENT

The KBTV ASOS has suffered a communications failure. The issue has been diagnosed, but there is currently no estimated time of return to service. The affected communications line is not serviced by the NWS. Terminal Aerodrome Forecasts will continue, but regular observations may not be available.

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.