textproduct: Burlington

WHAT HAS CHANGED

As of 630 AM EST Saturday...

Winter Storm Warnings and Winter Weather Advisories have been cancelled. Very light snow will continue through the morning before tapering off with minor accumulations less than half an inch expected.

KEY MESSAGES

As of 139 AM EST Saturday...

1. Snow showers will continue through the morning before gradually tapering off, with seasonably cool temperatures expected.

2. Low pressure system will track from the North Carolina coast northeastward towards the Gulf of Maine by Monday evening. Recent guidance has tracked closer north, which means snow is more likely to graze parts of southern and eastern Vermont. Additionally, gusty north winds to 35 mph are possible, and cold temperatures return behind the system on Tuesday.

3. Another round of widespread precipitation is possible over the latter half of the week.

DISCUSSION

As of 139 AM EST Saturday...

KEY MESSAGE 1: The period of heaviest snow has ended across the region, with snowfall expected to continue over the next several hours into the morning, gradually tapering off as the day progresses. Additional snowfall will generally be light this morning, with additional accumulations generally ranging from a dusting to a few inches, with the Winter Storm Warnings and Winter Weather Advisories still in effect until 10 AM this morning. While most of the snowfall is over, slick conditions may still be possible this morning, so be sure to use caution if traveling. A rather sharp temperature gradient looks to develop across the region today, with northern New York climbing into the 20s while southern Vermont warms into the mid to upper 30s. The colder air mass will set the stage for a seasonably chilly Saturday night as temperatures slip back into the teens and single digits.

KEY MESSAGE 2: Rapid cyclogenesis will be underway Sunday night into Monday as low pressure tracks off the Carolina Coast towards the Gulf of Maine. Different model scenarios have bumped northwards, and are quite intense, with most indicating surface pressures falling below 980mb, perhaps even down to 970mb. With the shift closer to the 40 N, 70 W benchmark, the probability of snow has increased for southern Vermont and eastern Vermont. We're still most likely to be grazed with very dry air on the northwestern periphery of the low. So outside the precipitation shield, it could be relatively clear in the subsidence section of the developing low. Once it reaches the Gulf of Maine, it'll pull the remnants of low pressure over the Great Lakes east back over us. The attendant moisture should produce some snow showers Monday night into Tuesday morning at the very least. The upcoming NBM 5.0 probabilities of 4" or more across Rutland and Windsor County are hovering around 30-40% with a sharp cut-off towards 0% over central Vermont.

One aspect of the system that we'll need to monitor is the strength of northerly flow. Over the last month or so, we've not had to think too much about wind gusts. But Monday into Monday night, a 1035mb surface high will approach James Bay as the surface low is reaching max intensity. The pressure gradient will be fairly sharp, but the tightest isobar contour packing is expected to be east of the region. Still, 850mb winds increase towards 40 knots, and the probability of gusts reaching about 30 mph is about 30-40% across much of the Champlain Valley into southern and central Vermont. Monday will be seasonably cool just below the freezing mark, but the cold air advection behind the departing coastal will push us about 10 degrees below normal in the teens and 20s Tuesday afternoon. Portions of northern New York could see wind chills Tuesday morning and early afternoon approaching 15 below. Tuesday night into Wednesday morning will feature min temperatures in the single digits above and below zero.

KEY MESSAGE 3: The next widespread precipitation that we will track is a pair of systems between Wednesday afternoon and Friday. It appears the set up involves a pair of systems, and modest model spread revolving around the degree of separation between the two systems exists. Where the systems are more closely entwined, there's less warm advection that takes place and more snow. This is more in line with the GEFS suite. A greater gap between the two means some light snow initially, but southwest, return flow is allowed to take place and warm us above freezing with a wintry mix or rain, which is closer to the EPS suite. As per usual, the GEPS finds a way to sit about right in the middle of the two. The AIGFS and EC's AIFS digs the second shortwave far enough south that the feature appears to behave like a coastal low, and that type of forecast would lean towards snow. With these scenarios being outlined, precipitation is likely, but the nature of how this plays out between Wednesday afternoon and Friday is uncertain.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Through 12Z Sunday...Strips of light snow continue to sink south across Vermont. Intervals of 2-6SM visibility and ceilings around 700-2500 ft agl are expected over the next 6 hours. Northwest to northeast winds will increase to 5-10 kts, remaining locally faster at KMSS, and that will eventually bring dry air to the region. Especially after 16-19z, there should be fairly quick improvement, though clearing may not make it to be KRUT or KSLK until about 03z-06z. After 20- 22z, winds will trend 5 knots or less, except terrain driven southeast flow will return at KRUT. Snow is likely to arc back into the region tonight into Sunday over northern New York, and noted a PROB30 for KMSS approaching 12z Sunday.

Outlook...

Sunday: Mainly VFR, with local MVFR possible. Slight chance SN. Sunday Night: Mainly VFR, with local MVFR possible. Slight chance SN. Monday: VFR. Chance SN. Monday Night: Mainly VFR, with areas MVFR possible. Slight chance SN. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: Mainly MVFR, with areas VFR possible. 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.