textproduct: Burlington

WHAT HAS CHANGED

As of 141 AM EST Thursday...

A Winter Storm Watch has been issued for Clinton and Essex Counties in New York, and along the spine of the southern Greens in Vermont for 10 AM Friday through 10 AM Saturday.

KEY MESSAGES

As of 141 AM EST Thursday...

1. A Winter Storm Watch is in effect 10 AM Friday to 10 AM Saturday along the southern Greens and far northeastern New York focusing along eastern slopes of the Adirondacks. The potential for 1"/hr snowfall rates during the Friday evening commute is the primary concern. Snow will be initially wet and then trend drier. So isolated power outages could occur.

2. Seasonably cool weather and occasional chances for precipitation are expected across the region this weekend into next week.

DISCUSSION

As of 141 AM EST Thursday...

KEY MESSAGE 1: Conditions will be quiet today and early Friday. A negative tilt upper trough embedded within an ambling upper low across the Great Lakes will coincide with a warm front that will overspread wintry precipitation across Vermont and northern New York Friday afternoon. A decaying zonal jet streak across the Canadian Maritimes and incoming southwest to northeast Jet into New York state will result in excellent upper divergence and strong frontogenesis that will be enhanced by the coupled jet structure. This will support an interval of moderate to heavy snow. Temperatures around 3000 ft agl are flirting right at 0 C, and surface temperatures in the lower valleys are likely to creep into the mid 30s. Some mixed precipitation types, or rain in warmer valleys, is possible before heavy snowfall rates and loss of daytime heating help us transition to entirely snow. Any ice will be marginal. The wet snow may be a concern for utilities, but the exact timing of the band seems like it could take place after the warm nose has begun to decay. So will note the potential for isolated power outages with initially wet snow, but it's possible lower snow-to-liquid ratios will be relatively shortlived.

Travel impacts will be likely for the Friday evening commute, though. Based on the latest HREF output, the 1"/hr probabilities begin about 18-19z (1-2PM) and max out about 21z-00z (4-7PM), mainly covering far northeastern New York state and much of Vermont. By 03z (10PM), better forcing shifts away. A backdoor front tied to an upper low in far northeastern Canada will cause our system to get absorbed, and dry air will also begin to infiltrate from the northeast. We may also have some squeeze play from the south in terms of a dry slot. So once we head into Friday night, snowfall rates will generally decline, and then by Saturday morning, snowfall will become very light. When all is said and done, a widespread 3-7" appears likely. Eastern facing foothills of southern Vermont and the Adirondacks appear the most likely to observe amounts approaching 7-9", and so the Winter Storm Watch highlights those regions. Forecast spread between the 25th and 75th percentile is rather large, and there is somewhat higher uncertainty due to the marginal temperatures, possible mix, and the fact most snow will be tied to the initial warm front. Stay tuned as we make updates later today.

KEY MESSAGE 2: Seasonably cool temperatures and occasional chances for precipitation are expected as we head into next week. High temperatures will generally be in the 20s to mid 30s as the week progresses, with overnight lows in single digits and teens most nights. A coastal low looks to develop Sunday into Monday, but it looks to track well to the southeast with little to no impacts expected across our forecast area. Another shortwave may bring some additional chances for showers early next week, but any accumulation would be minor. Another system looks to arrive towards the middle of next week, but there is still a good bit of uncertainty regarding this feature, although at this time it looks like much of the precipitation should fall as snow.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Through 12Z Friday...VFR conditions will prevail for most of the forecast period, with dry weather expected. Cloud cover will increase towards the later half of the forecast period, with ceilings lowering towards lower VFR and MVFR at the end of the forecast period and beyond. Winds throughout the forecast period will generally be northerly, although some terrain influences will be possible, especially after 00Z.

Outlook...

Friday: Mainly VFR, with areas MVFR and IFR possible. Definite SN, Definite FZRA, Chance RA. Friday Night: Mainly MVFR, with local IFR possible. Definite SN. Saturday: Mainly MVFR, with areas VFR possible. Chance SN. Saturday Night: Mainly VFR, with local MVFR possible. Slight chance SN. Sunday: Mainly VFR, with local MVFR possible. Slight chance SN. Sunday Night: Mainly MVFR, with areas VFR possible. Slight chance SN. Monday: Mainly VFR, with areas MVFR 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...Winter Storm Watch from Friday morning through Saturday morning for VTZ018>020. NY...Winter Storm Watch from Friday morning through Saturday morning for NYZ028-031-034-035.