929
FXUS61 KBTV 210221
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
921 PM EST Fri Dec 20 2024
.SYNOPSIS...
Widespread light snowfall is expected through Saturday morning
as a low pressure system passes well south of our region. Snow
will become showery during the day on Saturday and
orographically enhanced before coming to an end overnight. A
large ridge of surface high pressure will then settle over the
area and temperatures turn colder headed into the beginning of
next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 919 PM EST Friday...No significant changes were needed
with this update. Snow continues across much of the region this
evening, though some places in the Champlain Valley into the
western Greens have been in a bit of a lull. Radar shows snow
moving out of NY into western VT, so expect we`ll see things
pick back up here shortly. Temperatures have fallen some, though
not quite as quickly as previously anticipated, not surprising
given the cloud cover and winds. Have adjusted
temperatures/overnight lows accordingly, bumping up the
forecast a bit in the Adirondacks and Northeast Kingdom.
Otherwise the forecast remains in good shape and no other
changes were needed.
Previous discussion...Light snow has begun across our area, and
some light accumulations have been noted. Temperatures are
ranging through the 20s. Light snow will continue through the
overnight hours, then become more showery on Saturday as low
pressure system pulls eastward off the coast of New England. QPF
and snowfall will be light, due to lack of forcing. Generally a
quarter of an inch or less of QPF will yield around one to four
inches of snowfall. Highest snow totals will be along the spine
of the Greens with upslope snow showers adding to the totals
there Saturday into Saturday night. Snow will be very fluffy
with ratios around 17 to 1 expected. Even with the drier snow,
the evening commute will be impacted tonight. Minimum
temperatures overnight will dip into the single digits and teens
above zero, around 20 closest to Lake Champlain. Maximum
temperatures on Saturday will not go terribly far from the
overnight lows, generally only reaching the teens to lower 20s.
Much colder air will move into the region Saturday night, and
lows will dip into the single digits above and below zero.
Coldest spot will be in the more sheltered areas of the
Adirondacks where we are likely to see lows dip into the teens
below zero. Apparent temperatures overnight will be dangerously
cold.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
As of 332 PM EST Friday...With high pressure continuing over
the region, clear skies will make Sunday and Monday the best
options for pre-holiday travel. High pressure will keep
temperatures 10-15 degrees below average on Sunday, with highs
only in the single digits to mid-teens across the area. Lows on
Sunday night will bottom out in the single digits in the
Champlain and St. Lawrence Valleys, and 5-15 degrees below zero
in the Adirondacks and Greens. Wind chills will be 10-20 degrees
below zero with a steady 5-10 kt northwest wind. Extra care
should be taken by those venturing out Sunday night, as
frostbite can set in quickly under these conditions.
Mondays high will be slightly warmer, but still below normal,
with highs in the low-20s in the Champlain Valley, and upper-
teens in the mountains. Clouds and precipitation will slowly
return Monday afternoon ahead of a quick moving shortwave.
Precipitation will move into the St. Lawrence Valley Monday
evening and into the Champlain Valley and Greens by early
Tuesday morning. Precipitation types look to remain all snow
through the event. Winds will begin to increase on Lake
Champlain Monday night up to 25 kts on the broad waters as the
system approaches.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
As of 332 PM EST Friday...A white Christmas looks more and more
promising across the whole region. Snow showers and gusty winds
on Lake Champlain will continue through Tuesday morning into
Christmas Eve. The end timing of the precipitation remains
uncertain with how fast the system moves. The GFS keeps snow
showers through Christmas Eve with lingering showers early
Christmas Day, whereas the European model indicates a faster
moving system ending by late Tuesday night. With how quick the
system is forecasted to move, even with high SLRs, snow
accumulations will be light in the Champlain Valley, with higher
amounts possible in the mountains. The system will quickly move
off the coast on Wednesday, but become blocked off of the Mid-
Atlantic with high pressure off the coast of Maine. This
blocking pattern will help develop a breaking wave pattern
across the entire East Coast, with a pronounced ridge across
New England. This inverted Omega blocking pattern will prevent
any systems Thursday and Friday from moving into the BTV area,
and keep them to the south. A stationary front will stall out
along the Mason-Dixon line keeping temperatures in the region
fairly consistent for Thursday and Friday. High temperatures
will be in the low to mid-30s for the entirety of the area with
some upper-20s in the mountains.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Through 00Z Sunday...Very challenging aviation forecast for the
next 6 to 12 hours with highly changeable flight categories
expected associated with intervals of light snow. For example,
Rutland in the past 30 mins has jumped from IFR to VFR back to
IFR with vis and cigs. Expect this scenario to prevail thru 03z,
before northerly flow and additional moisture will produce high
probability of IFR cigs/vis. Also, as flow becomes strongly
blocked, expect mostly IFR at BTV for the next 6 to 12 hours.
Less confidence of IFR vis/cigs east of the Greens at EFK/MPV,
where intervals of are expected due to light snow. Similar type
scenario at SLK/MSS and PBG. As cold air advection continues
expect IFR to prevail thru 18z at SLK/BTV and RUT with interval
of MVFR/VFR conditions at other sites. Also, look for
north/northwest winds to increase at 10 to 15 knots with gusts
up to 20 knots, especially on Saturday. These winds and cold
temperatures will help to keep lake enhanced snow showers going
most of the day at BTV and RUT.
Outlook...
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. Likely SHSN.
Tuesday: MVFR. Chance SHSN.
Tuesday Night: Mainly MVFR, with areas VFR possible. Slight
chance SHSN.
Christmas Day: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Neiles
NEAR TERM...Hastings/Neiles
SHORT TERM...Danzig
LONG TERM...Danzig
AVIATION...Taber
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