textproduct: Burlington

WHAT HAS CHANGED

As of 149 PM EST Monday...

Brief mixed precipitation is possible late Tuesday night into early Wednesday morning, mainly across central/southern Vermont.

KEY MESSAGES

As of 149 PM EST Monday...

1. A light snowfall is likely across much of the area late Tuesday afternoon through the early overnight, possibly ending as a brief period of mixed precipitation and/or drizzle/freezing drizzle until sunrise Wednesday.

2. Confidence in widespread precipitation for the end of the week continues to increase, along with the potential for wintry mix and rain.

3. Anomalously warm temperatures, rain, and snowmelt likely for the weekend.

DISCUSSION

As of 149 PM EST Monday...

KEY MESSAGE 1: After high pressure exits the region tonight into Tuesday morning, a weak wave of low pressure will lift a remnant warm front from the Ohio Valley across the Mid-Atlantic states and central/southern portions of New England Tuesday afternoon and evening. As mentioned by the previous forecaster, the track and timing of precipitation has been pretty consistent from model run to run, but where uncertainly remains is how far north a warm layer aloft will track. Currently consensus points to the warm nose moving as far north as central Rutland/Windsor counties which will support a brief period of mixed precipitation from 03-09Z Wednesday where snow, freezing rain/drizzle are the likely ptypes. To the north, a wet snow will generally be the dominant ptype, but a growing dry slot in the DGZ early Wednesday morning could support northern areas finishing as spotty drizzle and/or freezing drizzle as well.

In general, this looks to be mainly a nuisance event with isothermal low level profiles supporting a wet (6-8:1) light snow of a dusting to 2", and some very light icing across Rutland/Windsor counties, mainly on elevated surfaces. Travel may be impacted overnight, but it should be noted that road surface temperature forecasts remain above freezing through much of the event which should limit impacts as well.

KEY MESSAGE 2: There remains no significant changes in the forecast for late this week, with continued confidence in chances for widespread precipitation both Thursday into Friday. Model guidance is in good agreement that a surface low will tack through the Ohio Valley and approach our region by late Thursday. The concern remains to be precipitation type. Most areas in the northern portions of the area should start off as mainly snow, but light easterly flow from an area of high pressure north of Maine would keep cold air locked in place east of the Greens and perhaps into portions of the Champlain Valley and the the northern St. Lawrence Valley. Modest 850mb southerly flow will advect warm air overtop of the cold air locked at the surface, resulting in a period of wintry mix, with freezing rain in the aforementioned areas. Cold air will likely hang on longer than the models have initialized, which bodes some confidence in a period of wintry mix over prevailing rain, and perhaps a longer period of snow east of the Greens. Furthermore, there is increasing confidence in cold air damming developing as the Thursday system arrives. The best chance for any precipitation will be south of US- 4, but most of the region should see some shower activity. Subtle changes to the Highs position, and low track will have significant impacts to the precipitation type. Please be sure to follow future forecast updates, especially if you will be traveling later Thursday into Friday.

KEY MESSAGE 3: The end of week surface low will wash out along a stalled boundary to the south of the region Friday as it runs into the high. This will set up our weather for the weekend with lingering moisture in the warm sector of an approaching shortwave trough from the northern Plains. Lingering moisture in the warm sector should remain aloft with continued south/southwesterly flow, however, cold air damming will remain with our high locked over the Canadian Maritimes, and coupled with diurnal cooling, continued shower chances Friday night into Saturday cannot be ruled out. The ptype remains uncertain, but with the aforementioned factors, a light wintry mix with freezing drizzle is possible into Saturday morning. The Plains shortwave will approach the area Saturday with a tightening pressure gradient blocked against the Greens with prevailing CAD. As a result, Saturday looks to be fairly breezy with strong waa and a 60-80kt 850mb jet overhead. A cold front looks to pass through sometime late Saturday with widespread rain expected. Current ensemble PWATs are nearing 1" areawide with the highest amounts across the St. Lawrence Valley. There is still considerable model spread with shower coverage and intensity, so be sure to continue to monitor the forecast, especially if planning any recreational activities with the warmer weather.

Regardless of the above uncertainty, it does still look like we should see much warmer temperatures for the weekend with highs surging into the 50s, with low to mid 40s for mountain summits. Lows will remain above freezing through the weekend. Total rainfall doesn't look overly concerning at this point, though rainfall with snowmelt will result in runoff into area rivers. An initial perusal of potential thawing degree hours for Friday through Sunday shows a range of 500 to 800 hours, which could be enough to cause some river ice movement. While widespread river ice breakup isn't expected, we'll continue to monitor trends moving forward. Near normal temperatures and continued shower chances will extend into next week.

AVIATION /18Z MONDAY THROUGH SATURDAY/

Through 18Z Tuesday...VFR conditions will continue through the entire TAF period with high pressure overhead and clear skies persisting. Winds will generally be light (under 10 knots) with mostly southerly winds in the wider valleys, and variable wind directions in the mountain sites. Winds will trend towards calm overnight, before becoming predominately southerly by tomorrow morning. Wind gusts will increase towards 20 knots in the Champlain Valley with south to north from channeled flow after sunrise tomorrow. Mid to high clouds will also increase from south to north by the end of the TAF period.

Outlook...

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

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.