Area Forecast Discussion
Issued by NWS Burlington, VT
Issued by NWS Burlington, VT
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055 FXUS61 KBTV 242040 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 340 PM EST Sun Nov 24 2024 .SYNOPSIS... A few additional showers and breezy conditions will continue this evening, with high pressure bringing a period of quiet weather for Monday. Another system will bring widespread rain to the region on Tuesday, with some pockets of freezing rain during the morning. A potentially more significant winter storm may follow for the Thanksgiving holiday. && .NEAR TERM /THROUGH MONDAY NIGHT/... As of 339 PM EST Sunday...Surface low pressure centered well to the northeast over the Canadian Maritimes will continue to bring a few additional showers and breezy winds to the region this evening. A brief period of high pressure will begin to build into the region, with shower activity tapering off into the overnight hours and winds trending lighter. Overnight lows will be seasonably cold with some partial clearing, with temperatures dropping into the 20s and even teens in portions of the Adirondacks. A period of quiet weather will continue through Monday with the high pressure overhead, bringing seasonable temperatures, dry weather, and even some sunshine. Temperatures during the day will warm into the upper 30s to lower 40s, with the Northeast Kingdom being on the cooler side due to lingering cloud cover. Overnight lows will drop into the 20s to near freezing in the broader valleys Monday night. A shortwave trough and associated frontal system will move in Monday night into Tuesday, which will bring another period of widespread precipitation to the region. Some areas of light freezing rain will be possible early Tuesday morning, with the greatest chances of ice accumulation across the higher elevations and locations east of the Green Mountains. Any ice accumulations, even just a glaze, can be hazardous and lead to slick conditions, so any motorists and pedestrians should be cautious. Temperatures should be warm enough in the Champlain Valley before the precipitation arrives to limit the potential for icy roads, but we will continue to monitor as we get closer. && .Short Term /Monday through Monday Night/... An unsettled start to the week is expected as widespread precipitation associated with a warm front moving through the region becomes showery. A few breaks in the showers may be possible as we head into the afternoon, although it will still be a bit dreary with plenty of cloud cover across the region and breezy winds. The warmest temperatures of the week are expected Monday afternoon, with highs in the 50s to near 60F in a few locations, which is about 10 degrees or so warmer that climatological normals for this time of year. Shower activity will redevelop Monday evening through the overnight hours as a cold front passes through the region, which much of the shower activity focused across the northern half of the forecast area. As the front moves through, winds will become more northwesterly, with upslope showers becoming more favorable. Snow levels will lower Monday night, with some snow mixing in, and light snow accumulations possible across the higher terrain, although any accumulations to be less than an inch. Overall rainfall amounts will be a few tenths of an inch, ranging from 0.5 inches across the Adirondacks and northern Greens to only 0.1 across parts of southern Vermont. Temperatures overnight Monday will cool into the 30s to near 40 in the broad valleys. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 307 PM EST Sunday...Lingering light rains and pockets of morning light freezing rain in eastern Vermont taper to scattered rain/snow showers by Tuesday afternoon as best forcing pushes east of the region. Brisk westerly flow in the lower to mid levels along with modestly strong cold thermal advection should allow some decent response off Lake Ontario with highest PoPs in downwind sections of the lake across the southern SLV and into the Dacks. Some of this may spill into the higher terrain of the Greens as well with coverage in these latter areas more heavily depending on the PBL wind direction. Regardless, some minor snow accumulations will be possible in the higher elevations of these areas into Tuesday night. Elsewhere, QPF will be very light to nil and will fall as light rain showers, at least during the daylight hours on Tuesday. Highs to top of in the 40s area wide with overnight lows from 25 to 35 under variable cloud cover and continued modest west/southwest flow. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 307 PM EST Sunday...The primary concern during the extended periods of the forecast is the larger-scale storm potentially affecting the region on Thanksgiving Day into Friday. Deterministic solutions remain in disagreement with each other, though are generally consistent with their respective ensemble members. While some output, such as this morning`s ECMWF output advertise a more impactful rain/snow system during this period, the GFS, GEM and their ensembles are less bullish showing a less amplified solution. A perusal of data suggests the differences are largely hinging on the elevation of 500 hPa troughing across south central Canada and a blocking upper ridge to its north in the Ungava/Davis Strait region. The GFS/GEM camp is showing this high latitude ridge as a stronger feature and suppressing heights slightly southward whereas the ECMWF less-so. Time will tell how this evolves, so for now will continue to offer solid chance (40-50%) PoPs for this period for mixed rains/snows and allow future forecasts to adjust accordingly once we attain better agreement. Behind the Thu/Fri system and toward next weekend there is broad agreement that overall heights will lower as fairly deep polar troughing settles southward across the northern tier of the CONUS east of the Rockies. As such, expect a trend toward colder than normal temperatures and periodic chances for snow showers here and there, especially in the snowbelts to the lee of Lake Ontario and across the northern higher terrain where additional light accumulations should be likely. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... Through 18Z Monday...A mix of VFR and MVFR across the region this afternoon, with a trend towards VFR throughout the forecast period. MVFR ceilings will linger at the higher elevation sites of KEFK and KSLK through much of the afternoon into the evening. A few light snow showers will also be possible for the first few hours of the forecast period at these sites, with occasional MVFR visibilities, but will taper off this evening. West winds will continue to be breezy, with gusts between 20 and 30 knots this afternoon, but will decrease later tonight. High pressure builds in to the region, bringing VFR conditions and lighter winds to all terminals around 12Z. Outlook... Monday Night: VFR. Chance RA, Slight chance FZRA. Tuesday: Mainly MVFR, with local VFR possible. Definite RA, Likely FZRA. Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHSN, Chance SHRA. Wednesday: Mainly VFR, with local MVFR possible. Chance SHSN, Slight chance SHRA. Wednesday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Thanksgiving Day: Mainly VFR, with local MVFR possible. Chance SN, Chance RA. Thursday Night: Mainly MVFR, with local IFR possible. Likely SN. Friday: Mainly MVFR, with local IFR possible. Likely SN. && .MARINE... Strong westerly winds have developed over Lake Champlain early this morning. Both the northern waters and broad lake are seeing sustained winds near 25 knots with higher gusts. Conditions will remain fairly consistent through the day with winds more markedly tapering off tonight. Wave heights should be 2 to 4 feet, with largest wave action over Burlington and Shelburne Bays given the favorable wind direction/largest fetch. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Kremer NEAR TERM...Kremer SHORT TERM...JMG LONG TERM...JMG AVIATION...Kremer MARINE...WFO BTV