textproduct: Burlington

WHAT HAS CHANGED

As of 204 PM EST Wednesday...

Models have trended farther south and drier for the system on Monday.

KEY MESSAGES

As of 204 PM EST Wednesday...

1. Heavy snow showers with possible snow squalls this afternoon.

2. Brief windy warm up Friday night into Saturday

3. Sharply colder temperatures returning late this weekend and early next week, then the potential for more precipitation and milder temperatures towards the middle of next week.

DISCUSSION

As of 204 PM EST Wednesday...

KEY MESSAGE 1: A prefrontal trough moves through this afternoon and evening, bringing some convective snow showers. Recent CAM runs have brought down the instability and organization of the snow showers this afternoon, so the chance of any specific area seeing a squall has decreased, but the threat is still there. Regardless, scattered heavy convective snow showers are still expected. The timing still looks to be mid afternoon for much of northern New York, early evening for the Champlain Valley and mid to late evening for the rest of Vermont. While there should be a more organized broken line moving through during the aforementioned timeline, a few snow showers will continue to be possible for a few hours after, though they will likely be lighter and more widely scattered. Overall, in terms of ingredients, the threat is definitely on the lower end. CAPE looks to max out over around 50 J, the frontogenesis should be relatively weak and there is not a significant wind shift or organized boundary.

KEY MESSAGE 2: A strong clipper passes by well to the north Friday night into Saturday, causing significant warm air advection. Its pressure looks to drop close to 980 mb, causing a southerly low level jet to pass overhead. Gusty channeled flow in the Champlain Valley and downsloping winds across the northern Adirondacks are likely. Temperatures should rise into the 40s for most places, with a run at 50 possible for parts of southern Vermont. The amount of warming looks to depend on the timing and make up of the cold frontal passage on the backside. An earlier passage would prevent the full effects of diurnal heating and some rain/snow showers with a prefrontal trough would cut back on temperatures, especially for northern areas. Dew points will be low regardless, so melting would be limited and any precipitation would cause notable wet-bulbing.

KEY MESSAGE 3: A cold front looks to push across the region Saturday night into Sunday, followed by surface high pressure centered over the Great Lakes/Canada, bringing some sharply colder temperatures and scattered snow showers Sunday morning. Highs for northern New York and Vermont on Sunday and Monday will be in the mid teens and 20s to start off meteorological spring. Lows over the weekend and early week will be as low as -15 to 5 F. This will be 15-20 degrees below seasonal normals (in both highs and lows) for early March. Probability of precipitation increases again in southern portions of the forecast area on Monday as a storm system cross the mid- Atlantic, but deterministic models are spread on how far north this system can get considering we'll likely have the Canadian high pressure pressing in from the north. Currently looking like the GFS is out of sync with the ECMWF and Canadian in bringing precipitation to our area. Temperatures look to trend towards seasonal averages into the midweek as another system approaches the region during the Tuesday-Wednesday time frame. Once again, the global models all agree there's something there, but don't quite agree on the timing/placement of precipitation. ECMWF is fastest with this wave with Canadian and GFS lagging behind. The timing of the system will also affect the timing and strength of potential milder air, so more details to come as we see more model consensus.

AVIATION /19Z WEDNESDAY THROUGH MONDAY/

Through 18Z Thursday...Scattered snow showers and possible embedded snow squalls will continue across northern New York and advance through Vermont this afternoon and evening. As of 18Z, snow showers have begun across northern New York where sites are seeing visibilities 4-7 miles. These snow showers are expected to continue and move eastward to all other sites by around 22Z-23Z Wednesday. These snow showers are also beginning to get heavier this afternoon, and they could produce vis 1-3 miles or less briefly for periods of time. KSLK is the most likely to have a sustained period of IFR vis through about 00Z Thursday. Probability of IFR vis drops significantly for all sites beyond 06Z Thursday, but lighter snow showers may linger on and off over the next 24 hours. Most sites are reporting ceilings around 1300-2700 feet above ground level outside of the Champlain Valley this afternoon, where ceilings remain 3800-4800+ feet. The Champlain Valley sites may briefly join in the MVFR ceilings around 02Z-04Z Thursday behind a line of snow showers, but there is also the likely scenario that they remain VFR cigs for the next 24 hours. Widespread VFR ceilings are anticipated to arrive around 04Z-05Z Thursday, potentially earlier at KMSS. Winds are currently gusting 15-25 knots out of the south and southeast at many sites, and this should continue until around after the line of snow showers moves through. Even then, some sites may continue to see breezy weather for the next 24 hours.

Outlook...

Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. Windy with gusts to 30 kt. NO SIG WX. Saturday: Mainly VFR, with local MVFR possible. NO SIG WX. Saturday Night: VFR. Chance SN. Sunday: Mainly VFR, with local MVFR possible. Chance SN. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX.

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. This communications line is not serviced by the NWS. 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.