textproduct: Burlington

WHAT HAS CHANGED

As of 115 AM EST Sunday...No significant changes were made to the forecast. Cold Weather Advisory will end this morning, but remain cold. Probabilistic data and a heavy mesoscale band suggest that snowfall amounts may approach 2 feet up through the spine of the southern Greens in Vermont, and that is being incorporated into the latest forecast.

KEY MESSAGES

As of 115 AM EST Sunday...

1. Sub-zero temperatures will conclude, but temperatures will remain plenty cold this afternoon with single digits to lower 10s.

2. A long duration, widespread moderate snow with a period of heavy snow in southern Vermont will produce 8-16 inches across the region and 13-19 inches in southeastern slopes of the Adirondacks and south-central Vermont. Localized snowfall totals up to 2 feet are possible in the southern Greens. Hazardous travel for both Monday commutes is expected.

3. Below normal temperatures are expected to continue across the region next week, with periods of isolated to scattered snow showers possible.

DISCUSSION

As of 115 AM EST Sunday...

KEY MESSAGE 1: Very cold weather has settled with radiational cool beneath strong 1040mb high. High clouds are beginning to thicken, and this will slow or reverse the rate of cooling. Everyone is below zero this morning, and cool air will remain relatively locked in as east to northeast flow and cloud cover won't support much warming. Temperatures should at least reach the single digits above zero lower 10s, and winds are not expected to be substantial. Still, subzero wind chills will continue across parts of the St. Lawrence Valley as low pressure approaches the Mid-Atlantic.

KEY MESSAGE 2: A significant winter storm remains on track for the region. A feed of moisture from the Eastern Pacific and steady warm advection will provide favorable conditions for a long stretch of moderate snow. Late this evening into early Monday morning, additional forcing from frontogenetic forcing and vorticity advection of a stretched out upper trough will produce a band of heavy snow across southern Vermont. It's a precarious balance of strong forcing and terrain shadowing as winds at 850mb increase to 40-45 knots. Dynamic forcing should overcome some of these nuanced features, but Rutland proper will likely be a relative minimum while southeast slopes of the Adirondacks and the southern Greens (like Ludlow) will have additional upslope enhancement. NBM probabilities of 2 feet have bumped up to 20-30% in these areas and are about 50- 60% for 18 inches. So the forecast has increased snowfall totals in those areass. The trick with these narrow bands of forcing is that it comes at the expense of regions farther north. High res ensembles, like the experimental REFS indicate the potential for 1"/hr snowfall rates doesn't really make it much farther north than Addison County. The current HREF 1"/hr probabilities do manage to make it north, but doesn't have the longevity of southern zones.

After 1 AM Monday, snowfall rates will begin to subside as the better forcing drags eastwards. However, steady snow will remain likely. So by the time 7 AM rolls around, there should already be about 5-8" north and 8-15" south already on the ground. This will impact the morning commute, and it's still going to be single-digit cold. Even though it's a fluffy snow, there will still be about 0.33- 0.66" of liquid. So take it slow and bundle up clearing things out.

Over the course of the afternoon, snow will reinvigorate after a morning lull as an inverted trough strengthens and perhaps closes off into a mid-level low. A small batch of increased FGEN at 925mb will likely develop and slide east. Additional snow accumulations of 3-7" is expected, and so the evening commute will likely also be messy. Snowfall will gradually subside Monday night.

.KEY MESSAGE 3: Below normal temperatures are expected to continue across the region next week, with periods of isolated to scattered snow showers possible.

Winter storm moves out the region Monday night and into Tuesday morning and behind it, cold and below normal temperatures move back in for next week. Daytime highs will stay in the teens throughout the week with overnight lows in the single digits above and below zero. Generally conditions will remain dry with a chance for some terrain driven snow showers Thursday into Friday as an upper low drops out of Canada, moving through the Great Lakes region and then into our area. There is not significant moisture associated with the system, hence, the best chances for precipitation will be terrain driven. Overall, a cold and quiet period is expected.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Through 06Z Monday...Strong high pressure will keep flight weather conditions VFR through 18z Sunday. Winds will be light overnight. Clouds increasing during the daytime hours Sunday. Chance for snow will begin from about 17z onward, and spread into our area from south to north. RUT and SLK will have snow by about 17z, then the rest of the terminals by 00z. Snow may be heavy at times, therefore IFR conditions will be intermittent with MVFR in lighter snow. Ceilings will drop to MVFR after 18Z for all terminals before dropping to IFR after 00Z.

EQUIPMENT

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. Use extra caution when navigating the broad waters of Lake Champlain. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

VT...Cold Weather Advisory until 7 AM EST this morning for VTZ003- 004-006>008-010-016>020. Winter Storm Warning from 1 PM this afternoon to 1 AM EST Tuesday for VTZ001>011-016>021. NY...Cold Weather Advisory until 7 AM EST this morning for NYZ026- 027-029>031-034. Winter Storm Warning from 1 PM this afternoon to 1 AM EST Tuesday for NYZ026>031-034-035-087.