textproduct: Burlington

WHAT HAS CHANGED

As of 136 PM EST Friday...

Winter Wx Advisory in effect for portions of central and northeast Vermont tonight.

KEY MESSAGES

As of 136 PM EST Friday...

1. Areas of freezing drizzle and freezing rain tonight across central and northeast Vermont.

2. Active weather continues by the middle of next week with a temperature roller coaster possible.

3. The potential for some river ice movement/breakup and the potential for a few ice jams remains possible later this weekend into early next week.

DISCUSSION

As of 136 PM EST Friday...

KEY MESSAGE 1: The forecast remains on track heading into the weekend which features low pressure tracking northeast through the Great Lakes and a persistent area of high pressure off the Atlantic seaboard. Strong south-southwesterly flow between these features will usher in a warm and moist airmass across the Northeast on Saturday with temperatures pushing well above seasonal normals. On the leading edge of the warm air advection CAMs came in with a bit more areal coverage of showers tonight into Saturday morning which for the most of the area won't present any type of hazard, but east of the Green Mountains we still expect temperatures to fall back below freezing tonight due to cold air damming. With above freezing temperatures moving in aloft, the expected precipitation type will be freezing rain for a short period of time before sunrise across portions of central and northeast Vermont. Therefore, we've gone ahead and issued a Winter Wx Advisory for light icing up to a tenth of an inch. After sunrise, temps warm significantly above freezing ending the threat, with showers continuing across much of the region through about noon followed by a brief lull, then more showers and possibly a few rumbles of thunder late afternoon through Saturday night along a frontal passage. Winds will be additionally gusty tonight through Saturday as a developing 925-850mb low-level jet builds over the region and will support strong surface wind gusts from the SSW 35-45 mph, especially in the Champlain and St. Lawrence Valleys.

KEY MESSAGE 2: Uncertainty remains in the forecast, mainly in regard to the middle portions of next week in regard to p-type. The main player will be an expansive, late season arctic high off to our north across southern Quebec and its associated frontal zone. The latter feature should be draped somewhere near our area, so its placement north/south by Wed/Wed Nt will be critical on eventual amounts of wintry precipitation (or not) as low pressure rides along the boundary. Deterministic models remain all over the place with the latitudinal placement of the front, and given a higher than normal confidence of a sharp north-south baroclinicity across the boundary it's wise not to discount any solution at this point. We should know more in the next few days. By late week a general trend toward a more quiet, seasonably cool weather pattern is expected.

KEY MESSAGE 3: Given milder air pushing into our region over the weekend and into early next week, some slight to modest river rises are forecast. While widespread flooding is not expected, these rises may be enough, in some cases, to foster partial river ice movement and/or breakup. If that scenario pans out, a few ice jams and associated flooding may be possible. However, confidence is not high enough at this point to warrant a Flood Watch. As always, it's nearly impossible to predict the exact location of any potential jams, but with the predicted milder weather conditions will be monitored closely going forward over the coming days.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Through 18Z Saturday...An area of low pressure currently crossing the Midwest will pass through the Great Lakes and dive across the mid- Atlantic tonight through Saturday night. Several wider valley locations continue to report below freezing temperatures even into the afternoon today, including MSS and PBG, where cold surface air will linger. Any of the colder hollows of the region will also likely see temperatures fall quickly below freezing tonight, including SLK, EFK, and MPV. This will contrast sharply with warm air aloft advecting into the region over the next 24 hours. We're also seeing plenty of moisture throughout the atmospheric column, indicating a relatively misty and drizzle-infused period, though increasing winds should keep sustained fog from forming. Ceilings across the region are largely VFR this afternoon outside the blocked flow 1400-1900 foot clouds across central and southern Vermont. We expect clouds to lower for all other sites around 00Z-06Z Saturday to MVFR levels or lower. We are also forecasting winds to increase over the next few hours out of the south, gusting 20-35 knots or higher by 00Z-12Z Saturday, though southern Vermont may see decreased gusts, instead mainly sustained winds 5-15 knots out of the south-southeast at RUT. A strong southwesterly low level jet 35-55 knots will make for potent and long-lasting low level wind shear at all sites, primarily 03Z Saturday onwards. Freezing drizzle is possible at MPV tonight and would begin around 05Z-07Z Saturday, changing over to freezing rain around 08Z-10Z Saturday as forcing increases. Another site that has the potential for some patchy freezing drizzle is SLK, though that should quickly turn to plain drizzle, light rain showers, or mist as surface temperatures rise more quickly across northern New York. Elsewhere, rain showers are forecast starting around 08Z-12Z Saturday. Ceilings will also continue lowering during this time, and widespread IFR cigs are anticipated around 06Z-12Z Saturday, lasting at most sites through 18Z. Gusty southerly winds will be their highest around 12Z through 18Z Saturday with localized enhancements in the Champlain Valley due to channeling and in the northern Adirondacks due to downsloping. Peak winds will be 30-40 knots at BTV and PBG during this period.

Outlook...

Saturday Night: MVFR/IFR conditions possible. Definite SHRA. Sunday: Mainly MVFR, with areas VFR possible. Chance SHRA. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Chance RA. Wednesday: Mainly MVFR, with areas IFR possible. Definite 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...Winter Weather Advisory from 7 PM this evening to 7 AM EST Saturday for VTZ003-004-006>008-010. NY...None.