Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 141713 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1213 PM EST Thu Dec 14 2017 .SYNOPSIS... Cold temperatures are here and will remain through the weekend. There is a chance for some light snow showers Friday night into Saturday. Temperatures will moderate next week. && .NEAR TERM /THROUGH FRIDAY/... As of 932 AM EST Thursday...Forecast for today remains in excellent shape with only minor changes needed to blend hourly temperatures with the latest observations. Previous Discussion...Dry and cold weather will be the main story for today through Friday with cold surface high pressure ridge over us. Maximum temperatures will top out in the single digits and teens today which is about 15 to 20 degrees below seasonal normals. Our region is under a very cold airmass, the coldest of this meteorological winter season so far. 850 temperatures will dip to about -20 C this afternoon. Although it will be a cold day, winds will be generally light and will see some sunny skies this afternoon so not a terrible day. As previous forecaster mentioned...atop the high peaks, temps will barely touch zero, and winds will be brisk in the 20-30 mph range, wind chills will push into the -20 to -30 below zero range. Tonight will be cold as well though the air mass will slowly be warming for tonight and Friday. Another weak low pressure system approaches the area Friday, and the flow ahead of this low will become favorable briefly for some lake effect snow showers in extreme southern Saint Lawrence county. Temperatures Fri will be a bit warmer but still colder than seasonal normals, generally teens to lower 20s with increasing cloud cover through the day. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 405 AM EST Thursday...A weak shortwave clipper system will be tracking through the Great Lakes which will bring some warmer air initially through the evening hours for most of the north country. The track of the surface low looks to track from Lake Huron southeast through Lake Ontario. This should lead to a long southwesterly fetch and resulting lake effect snow event off Lake Ontario. Based on the NAM and CMC it looks like the snow should only impact Saint Lawrence county for a 6-9 hour window. BUFkit soundings indicated the lake induced CAPE should be in the 400-500 J/kg based on a lake temp of 42F and 850mb temp of -11C. The issue preventing me from going with large snow totals just yet is the short window and the high shear during the event. So I`ve gone with a general 3-4" generally up the Saint Lawrence river and between 1-3" as the band drifts to the south. We`ll also need to continue to watch for the potential for snow squalls across Northern New York on Saturday as the 925mb thermal gradient is quite sharp and the Snow Squall parameter is indicated the potential for some squalls generally over the Adirondacks based on a local 4km WRF model. As the 700mb trough enters the region it will shut off the lake effect snow by mid day on Saturday and usher in a return of colder temps. Expect lows during the warm advection on Friday night in the teens and after the front Saturday lows Saturday night will be in the low single digits. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 415 AM EST Thursday....Sunday and Sunday night should be fairly quiet with ridging at the surface and zonal flow aloft. There still seems to be some inconsistencies with what happens coming out of the weekend. The GFS still points to a null event but the CMC and EC show a weak shortwave bringing a reinforcing shot of warm advection snow to the region. QPF totals aren`t really on the high side but nonetheless there should be some accumulating snow Monday during the morning and into the afternoon. Temperatures will be the more challenging issue as we`ll see a moderating trend with highs in the valleys in the mid 30s on Monday and near 40 on Tuesday. So the natural issue with warming temps will be p-type concerns on Tuesday. At this time given the amount of variability, and how a degree or two makes the difference between rain/sleet/snow, I`ve just left mention of rain/snow based on the boundary layer averaged temp for Tuesday morning. By Wednesday the front from the system should be through the region and we return to near normal temps with highs in the upper 20s to low 30s in the valleys. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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Through 12Z Thursday...VFR conditions will continue through the period. Clear skies this afternoon and evening will give way to increasing mid/high clouds from the west/southwest after daybreak with a gradual lowering from 100-250 west to east at 12Z, to 040-080 by 18z. Winds 8-12kts from the west/northwest shift to the south/southwest after 12z. Outlook... Friday Night: Mainly VFR, with local MVFR possible. Chance SHSN. Saturday: Mainly VFR, with local MVFR possible. Chance SHSN. Saturday Night: VFR. NO SIG WX. Sunday: VFR. Slight chance SHSN. Sunday Night: VFR. Chance SHSN. Monday: VFR. Chance SHSN. Monday Night: Mainly MVFR, with local IFR possible. Chance SHSN. Tuesday: Mainly MVFR, with local IFR possible. Chance SHSN, Chance SHRA.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Neiles NEAR TERM...Lahiff/Neiles SHORT TERM...Deal LONG TERM...Deal AVIATION...Lahiff is the U.S. government's official web portal to all federal, state and local government web resources and services.