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FXUS61 KBTV 212018
Area Forecast Discussion
National Weather Service Burlington VT
318 PM EST Tue Nov 21 2017
Milder but breezy weather is expected for this afternoon with
highs in ranging from the mid 40s to mid 50s. A cold front will
move through the region late tonight and Wednesday, bringing
scattered rain and snow showers. Thanksgiving Day is expected to
be dry with temperatures in the 30s.
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 318 PM EST Tuesday...After a mild afternoon with high
temperatures in the upper 40s to mid 50s, a cold front will
approach the region from the west overnight reaching the St
Lawrence valley around 09z, then moving east into the Champlain
Valley just after 12z, and CT valley by 16z. A band of
precipitation will accompany the front and boundary layer
temperatures should be warm enough to support mainly just rain
showers as 925mb temps don`t drop below 0c until the front
passes. It should be cold enough in the higher elevations to
support a change to snow showers as the front moves by. Not
expecting much in the way of rain or snow accumulation with
perhaps a tenth or two of QPF mainly rain, but mainly snow at
the mountain summits for 1-3" above 3000 ft and an inch or less
down to the bases of the mountains as temperatures drop.
Tomorrow morning any lingering orographically driven rain/snow
showers in the valleys and snow showers in the higher terrain
will gradually wind down during the afternoon. Expecting
temperatures to hold fairly steady from around 30 in the
Adirondacks to 40 in the valleys before falling again toward
Should be quiet Wednesday night as a weak ridge of high pressure
builds in from the west and height rise aloft. Still could be
some pesky clouds hanging on in the mountains with low temps
ranging from the mid teens to mid 20s depending upon cloud
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 318 PM EST Tuesday...12z guidance still all indicate that
Turkey Day daytime will be uneventful weatherwise. Ridge of
surface high pressure over the area will keep us dry. However,
clouds will be on the increase as a weak upper trough and
surface cold front quickly approaches from the west. With 925mb
temperatures around -5C, daytime highs will be seasonably cool
and generally in the low-mid 30s.
The surface high moves off to the east as the trough and cold
front approaches, and causes the low/mid level flow to become
more southwesterly. The trough and relatively cold air aloft
will help to activate some lake effect snow showers off Lake
Ontario late in the day and during the evening. With the
southwest flow, expect snow showers to push into the St Lawrence
Valley and western part of the `Dacks. This moisture will also
get entrained into the overall trough and advected toward
northern Vermont during the overnight hours. Have used a blend
of guidance for the precipitation probability forecasts, with a
little extra detail in timing/placement via the BTV 4km WRF
output, resulting in roughly 30- 45% PoPs across parts of
northern NY diminishing to 15-25% for the higher terrain of
northern Vermont. Net result is that we`ll probably see about 1"
of snow across parts of northern NY, with just a coating in
northern VT at best.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 318 PM EST Tuesday...While the long term period continues
to look active, there are no really no big systems on the
horizon to speak of. The tail end of a decaying cold front will
bring some scattered snow showers to the region Thursday night
into Friday morning, followed by brief high pressure for the
remainder of Friday into early Friday night. The weekend
continues to look unsettled, but the latest trends are for one
area of low pressure to track well north of the region, and
another well offshore on Saturday, both delivering limited
impacts to the northeast. The best chance for precipitation
actually now appears to be post-frontal passage Saturday
afternoon/night and through the weekend where upslope flow will
enhance snow shower activity across the higher elevations. It
will be noticeably warmer for Friday and Saturday though with
deep southwesterly flow developing aloft. Highs should bump into
the 30s/40s before falling back into the 20s/30s for
Sunday/Monday as the upper trough settles overhead.
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
Through 18z Wednesday...VFR but with south to southwest winds
gusting 25-35 kt until just before sunset. Clouds and rain showers
will begin to move into the area from the west tonight ahead of
a cold front reaching near BTV near 12z with ceilings lowering
to MVFR. Winds will be shifting to WNW around 10 kt behind the
front and falling temperatures will bring a change to snow
showers and IFR vsby mainly at SLK tonight and MPV tomorrow
morning. Not expecting much of accumulation but could be a
coating at SLK.
Wednesday Night: VFR. NO SIG WX.
Thanksgiving Day: VFR. NO SIG WX.
Thursday Night: MVFR. Chance SHSN.
Friday: Mainly VFR, with local MVFR possible. Slight chance SHSN.
Friday Night: VFR. Slight chance SHSN.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA,
Saturday Night: MVFR/IFR conditions possible. Chance SHSN, Chance
Sunday: Mainly MVFR, with local IFR possible. Chance SHSN.
As of 318 PM EST Tuesday...Lake wind advisory in effect for
south winds 20-30 kts with gusts to 35 knots with significant
wave heights 3 to 6 ft through the evening hours. Gusty south
winds will gradually diminish overnight then shift to the west
then northwest at 10 to 15 knots on Wednesday.