Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 290558 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1258 AM EST Sat Feb 29 2020 .SYNOPSIS... Aside from a few mountain snow showers, a few cool, dry days are in store for the weekend. Several chances for light precipitation exists next week along with a warming trend taking temperatures into the upper thirties to lower forties for day time max temperatures. && .NEAR TERM /THROUGH SUNDAY/... As of 1252 AM EST Saturday...Lake effect snow band has drifted south and only light snow showers are anticipated through the overnight. Have cancelled our hazards with this update. Previous discussion follows. As with the previous evening update, the primary issue was accounting for the latest radar trends. The lake-effect snow band has intensified somewhat as it accelerates southeastward, currently just south of a line from Saranac Lake, NY to Plattsburgh, VT to Enosburg, VT. An updated special weather statement has been put out at this hour to caution motorists for rapidly changing conditions tonight in association with this heavy snow, as visibility drops below a half-mile in this band. Also noticed on webcams snow persisting in places such as Springfield and St. Johnsbury in Vermont, so bumped up precipitation chances there in the near term. Otherwise, just minor tweaks made to winds and temperatures with going forecast looking good. Previous discussion...Lake effect warning for southeastern St. Lawrence and Winter Weather Advisories have been extended to 5 AM. Additionally, southwestern St. Lawrence has been added, as 3"-6" accumulations are expected with locally up to 7" towards areas like Gouverneur, Edwards, and Fowler. Based on reports of observed 5"-8" of snow observed over northern Vermont, have updated to forecast snow totals provide an additional 2" to 5". Thus, Winter Weather Advisories have also been published for northern Vermont covering Franklin County eastward to the Northeast Kingdom through 1 AM. Outside of the warning area, additional accumulations of a dusting to 2" are expected. Visible satellite is quite gorgeous today. One can see the curl of mid to upper clouds influenced by the closed upper low just north of the International Border. The individual cells of lake effect snow showers embedded within lengthy lake effect snow bands are also visible in stunning detail on satellite imagery. Cannot reiterate enough how wonderful GOES-16 is. A subtle near surface boundary is lifting northward in a line from southern St. Lawrence through Chittenden and up to the Northeast Kingdom of Vermont. Lake effect has been streaming parallel to this boundary and to the north. As this lifts northward, expect the lake effect snow showers to push northward towards the International Border. Gustier winds lie south of the boundary, where there are even pockets of sunlight at times. Overall, not seeing much blowing snow. Forecast shows less blowing snow potential over the coming hours, and think this is reasonable. With the higher solar angle and with temperatures near enough to the melting point, think enough melting and compaction is taking place to mitigate this factor. A bit further south is lake effect snow streaming all the way from Lake Erie, though snowfall reports are a bit more sporadic out of this band based on surface observations. After sunset, a strong shortwave currently digging across Michigan will quickly eject eastward, and will push the lake effect band back to the south later tonight into the overnight hours. Lake effect snow should cease by dawn Saturday. With the upper low meandering in place on Saturday and with adequate low-level moisture and modest lapse rates in place, anticipate upslope snow showers to linger over the higher summits. Summit snow showers could briefly retreat westward downhill with mostly diurnal fluctuations impacting stability and as wind speeds decrease behind the mid-level front, but accumulations will be marginal at best. Pressure gradients will remain a bit constricted, so there should at least be some winds still out of the northwest. Source air mass is pretty chilly, so a few below average days are on tap. Lows tonight will be in the upper single digits to mid teens. Highs on Saturday will hover around the upper teens to lower 20s, and then the overnight lows on Saturday into Sunday morning will settle into the single digits above zero for most areas. && .SHORT TERM /SUNDAY NIGHT/... As of 340 PM EST Friday...Quiet period of weather Sunday as upper level ridging begins to build in. NW flow aloft will keep lingering clouds across the high terrain through the morning hours, but eventually drier air should work its way south and bring about mostly sunny skies. Should be a relatively nice day with below normal temperatures in the mid 20s with near normal temperatures Sunday night in the mid teens. Non-diurnal temperatures on Sunday night will see lows early in the night as high pressure crests overhead. Our next approaching system approaches from the west with increasing southwesterly winds Sunday night and like precipitation Monday morning. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 340 PM EST Friday...Relatively active period of weather for the first part of the long term with the potential for very light mixed precipitation Monday morning. Have only run with rain/snow surface T as degree of warm nose is questionable and precipitation amounts are very light (only a few hundreths). Soundings indicate the potential for some light sleet but given degree of warm nose is incredibly slight and model variability have kept things simple at this time. Temperatures warm to spring readings in the low to mid 40s Monday through Thursday. A weak clipper will track across bring with it a chance for rain Tuesday night. Again precipitation remains quite light with QPF amounts less than 0.10". After this, quite a large degree of uncertainty for timing and evolution of next storm with CMC/ICON/ECMWF showing high pressure building south out of Canada with moisture streaming from the Gulf of Mexico staying suppressed to our south. Currently, GFS is outlier with highly amplified large scale pattern over eastern CONUS and potential for either heavy rain or a quick shot of snow for Wednesday. Have offered generally 40-50% PoPs for mid week to handle this variability. Will dial in this forecast (for more snow, finger crossed) over the weekend. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Through 06Z Sunday...Lake effect snow band across our area is drifting south and diminishing a bit. May still have some light mountain snow showers overnight, mainly covered this with VCSH. Some lingering MVFR ceilings, but conditions generally improving through the 24 hour TAF forecast period. Outlook... Sunday: VFR. NO SIG WX. Sunday Night: VFR. Chance SHSN. Monday: Mainly MVFR, with areas VFR possible. Chance SHRA, Chance SHSN. Monday Night: Mainly IFR, with areas MVFR possible. Chance SHRA, Chance SHSN. Tuesday: Mainly VFR, with local IFR possible. Chance SHRA, Chance SHSN. Tuesday Night: Mainly MVFR, with areas IFR possible. Chance SHSN, Slight chance SHRA. Wednesday: MVFR/IFR conditions possible. Likely SHRA, Likely SHSN. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Haynes NEAR TERM...Haynes/Kutikoff/Neiles SHORT TERM...LaRocca LONG TERM...LaRocca AVIATION...Neiles is the U.S. government's official web portal to all federal, state and local government web resources and services.