802 FXUS61 KBTV 291157 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 657 AM EST Wed Dec 29 2021 .SYNOPSIS... A relatively mild late December pattern will remain in place across Vermont and northern New York over the next several days, as southwesterly flow remains in place aloft. A few minor troughs embedded in the southwesterly flow will bring chances for very light snow or patchy freezing drizzle, mainly Thursday and Thursday night. A more significant low pressure system is expected to bring widespread rain to the North Country Saturday into Saturday night. Some areas of mixed precipitation are possible, especially across northeastern Vermont and the St. Lawrence Valley of far northern New York. Precipitation may end as snow or snow showers, as much colder air arrives in a shift to northwesterly flow to start next week. && .NEAR TERM /THROUGH THURSDAY/... As of 647 AM EST Wednesday...No significant changes needed to the forecast with the sunrise update. Overall, not much in terms of noteworthy large-scale/synoptic wx features today and tonight, with low cloud trends the primary forecast challenge. Main frontal zone remains well south of our region, oriented W-E across central PA into NJ/NYC area. Associated light precipitation associated with the frontal zone generally remains south of our forecast area today, with just a slight chance of a few snow showers across south- central VT. Meanwhile, a weak surface ridge extends from near James Bay southeast across Quebec into Northern New England. Overall pressure field will remain rather flat with weak wind fields across our region over the next 24-36 hrs. This will allow prevailing low cloudiness to linger, though a few afternoon sunny breaks are expected with modest mid-level drying pushing in from the north. Looking for afternoon highs once again in the mid-30s for most valley locations, except low-30s across the St. Lawrence Valley and Vermont's Northeast Kingdom. For tonight, modest increase in 950-850mb swly flow allows moisture/low clouds from frontal zone to redevelop into our region. Precipitation generally not expected, but the cloud cover should hold temperatures in the upper 20s to lower 30s for much of our region, except low-mid 20s near the Intl Border where low cloudiness arrives late. For Thursday, low-level wind fields very light below 850mb, but an embedded mid-level shortwave trough in wswly flow will bring a chance of a few snow showers during the daylight hours. Included 20- 30% PoPs, with best potential for light snow shower activity across the higher terrain. Little or no snow accumulation expected. Temperatures will again rise above freezing in most locations for highs Thursday afternoon. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... As of 347 AM EST Wednesday...Thursday night into Friday will be rather dreary with forecast soundings indicating drying aloft but plenty of low-level moisture remaining over the area. Zonal progressive flow aloft will move an elongated shortwave through which will bring some very light precipitation to the area. Most of the moisture will be in the low levels with the snow growth zone becoming unsaturated Thursday night. This will favor flurries/very light snow/freezing drizzle ("snizzle") overnight becoming spotty light rain showers with some occasional patchy drizzle during the day Friday as temperatures warm into the mid 30s to low 40s. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 347 AM EST Wednesday...Continuing to watch a complex system that will move through this weekend, bringing a variety of precipitation types to the North Country. Although exact details still remain murky, models are starting to come into slightly better alignment on the broad idea of how the system will evolve. The first phase of the system will occur Friday night/Saturday morning as a warm front pushes through the area. For the most part, little fanfare expected as the initial warm front pushes through due to lack of deep moisture...however some freezing drizzle/very light mixed precipitation is possible during the overnight hours. A warm nose pushing through over sub-freezing surface air (especially over eastern Vermont) could support the potential for some freezing rain overnight, however (luckily) there just doesn't look to be much QPF associated with the warm front passage so icing potential will be quite limited. During the day on Saturday, widespread precipitation will develop as the surface low tracks through the area. Exact track of the low remains to be determined, but it looks to track northeastward somewhere in the vicinity of our forecast area. The proximity of the low to our forecast area makes for a tricky forecast...a more southern track would suggest more mixed precipitation and a more northern track would suggest more rain. At this point, it looks like the majority of the precipitation on Saturday will fall as rain for much of our forecast area, though subtle changes in the low track could change that. One possibility that we are watching closely is a low track to the south of the Saint Lawrence Valley, which would result in persisting northeasterly flow down the valley and a resultant shallow cold layer near the surface. This scenario would favor freezing rain for the Saint Lawrence Valley. At this point, still too early to determine the exact low track, so all possibilities are still on the table. For Saturday night, the low and mid-levels will begin to cool, resulting in a transition from rain to some snow showers behind the system. A sharp cold front will move through during the day Sunday, briefly reinvigorating showers as low-level lapse rates steepen. The cold front passage will be followed by the arrival of an arctic air mass, which will bring noticeably colder temperatures to start the next work week. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... Through 12Z Thursday...Light winds and a mix of MVFR and VFR ceilings will characterize the TAF period. Ceilings have generally improved back to VFR during the pre-dawn hours, with the exception of PBG and EFK, where MVFR ceilings persist. Also, seeing HIR TRRN OBSCD in both the Adirondacks and in the Green Mtns. Do anticipate ceilings improving to VFR at PBG by 14Z, but may remain lower at EFK with weak wind fields in place. Lower ceilings return this evening and tonight from south to north, with most TAF locations returning to MVFR category ceilings. A stray flurry or two is possible early this morning, but generally vsby expected to be unrestricted through 12Z Thursday. Light and variable winds areawide, locally NE 5-8kts at KMSS. Outlook... Thursday: Mainly MVFR, with local IFR possible. Chance SHRA, Slight chance DZ, Slight chance SHSN. Thursday Night: Mainly IFR, with areas MVFR possible. Chance SHSN, Chance SHRA, Slight chance DZ. Friday: Mainly MVFR, with areas IFR possible. NO SIG WX. Friday Night: MVFR/IFR conditions possible. Chance RA, Slight chance SN. New Years Day: Mainly IFR, with areas MVFR possible. Likely RA, Likely SN. Saturday Night: Mainly IFR, with local MVFR possible. Chance SN, Chance RA. Sunday: Mainly MVFR, with local IFR possible. Chance SHSN. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos NEAR TERM...Banacos SHORT TERM...Duell LONG TERM...Duell AVIATION...Banacos