405
FXUS61 KBTV 181731
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1231 PM EST Thu Dec 18 2025

.SYNOPSIS...
A strong frontal system will approach the region today with
increasing gusts up to 45 to 55 MPH and warming temperatures by
tonight. Widespread rain arrives tonight with a period of heavy rain
Friday. Gusty winds continue through Friday with a strong cold front
changing rain over to snow. Winds turn westerly with gusts favoring
the more downslope area Friday night with colder conditions
continuing into the weekend.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 1047 AM EST Thursday...Quick update to hoist wind advisory
for our entire cwa thru 18z Friday. Still very difficult to
determine amount of mixing, but low level winds are very strong
and feel given line of showers moving across our cwa on Friday
morning, the potential to mix some winds to the surface supports
the advisory. We will share additional thoughts with our
complete package early this afternoon.

Previous discussion below:
Quick update to adjust temperatures some more. Massena and the
northern St. Lawrence Valley have been under light northwest
drainage flow this morning contributing to temperatures in the
upper teens to near 20 which should continue for a few more
hours. Additionally, 06Z guidance has continued the trend
towards the NAM higher gusts Fri afternoon/evening across VT, so
have nudged further towards these higher solutions, though
still just below advisory criteria. I expected we may need
additional advisories for Vermont for Friday for within the cold
front and once winds switch to the west.

Previous Discussion...Still anticipating an active period of
weather today thru Friday with gusty winds, changing temps, and
locally heavy rainfall.

No major changes to the original forecast but trends continue to
favor slightly stronger gusts with the 00Z guidance. A amplifying
mid/upper level trough will swing out of the central Plain and Great
Lakes later today with a deepening 983mb surface low. The
strongly amplified pattern will help to advect deep layer
moisture from the Gulf in addition to strong waa from southerly
flow. Temperatures and dewpoints out ahead of the system are
already running in the 90th percentile of guidance with some
cloud cover aiding in limiting radiative cooling. A potent jet
streak with a 70 to 85 kt low level jet will be responsible for
the main weather impacts from this system. The uncertainty and
difficulty with this forecast remains how mixed the boundary
layer can become and how much of these strong low level jet
winds will be fully realized at the surface. The core of the
winds arrive late this morning into early afternoon across the
Adirondacks as flow becomes parallel to the St. Lawrence Valley.
Gusts up to 40 mph are likely through this afternoon,
increasing further by tonight up to 55 mph. Leaned about 20%
into the higher guidance of winds, however, given the presence
of a surface inversion, and concurrent precipitation, gusts
still remain below high wind warning criteria and thus did not
adjust the current Wind Advisory details. HREF probabilities of
>60 mph are still around 60% in general, but the spatial
coverage has become more confined to the US Route 11 corridor
near Malone, supporting the idea of Wind Advisory Gusts and
more localized higher gusts. The strongest gusts will generally
be between 9 PM and 7 AM Friday when winds will shift to the
west with an approaching cold front. Gusts could spike to High
Wind Warning criteria for a brief hour as the cold front passes
through the Champlain Valley Friday midday, but these localized
stronger gusts will be very short lived, and weaken back toward
the prevailing 40-50 MPH gusts. Winds will continue to be gusty
through the day Friday.

Temperatures will be a roller coaster through today and tomorrow
with strong 925 to 850mb waa. With temperatures this morning already
in the 75-90th percentile, highs today should be able to reach the
the low 40s. Localized northwest flow in the St. Lawrence Valley may
be able to limit the strong caa briefly keeping northern New York
below 40, but as flow becomes predominately southerly, temperatures
will become non-diurnal tonight with increasing temperatures. Behind
a warm front Friday morning, continued waa in the warm sector should
push Friday highs above daily record territory towards the mid to
upper 40s and perhaps near 50 at BTV. As an associated cold front
pass through Friday midday, temperatures will quickly fall back
towards freezing by late Friday.

Precipitation will begin as rain for most locations tonight, with a
few flakes in the higher terrain as cold air will be harder to scour
out initially. Pwats will be around 1" or 200 to 300% of normal
for this time of year given the strongly amplified flow pattern
and strong low level jet. The bulk of the precipitation will
fall Friday morning into early Friday afternoon associated with
the cold front. 850mb frontogenesis will support a band of
moderate to heavy rain between 7 AM and 1 PM Friday as the cold
front crosses the region. Behind this band, as temperatures
fall back towards freezing, rain will change over to snow for
the northern Adirondacks and central and northern Greens with a
few inches of snow possible above 1200 ft. Given the strong
gusts and flow aloft, anticipate some downslope effects across
the eastern Adirondacks and Champlain Valley. Rainfall totals
are generally in the 0.5-1.25 inch range, with potentially some
higher amounts in the Adirondacks and spine of the Greens. Some
rivers may see bankfull with the combination of rainfall and
snow melt. See hydro section below for additional details.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 236 AM EST Thursday...Behind a cold front Friday, winds will
turn to the west and remain on the gusty side, with the strongest
winds favoring the downslope regions of the eastern Adirondacks and
eastern Greens. The NAM3K continues to be the highest with gusts up
to 50 knots, however, the HRRR, which tends to perform better under
strong forcing and inversion set ups is lower towards 30-40 kts.
HREF probabilities of >40 MPH range from 40-60%, with higher
probabilities into the southern Greens south of Killington. The
southern Greens will have the best shot of any Wind Advisory
criteria Friday night, as precipitation tapers off and becomes
confined to the central and northern Greens, and Adirondacks.

Behind the cold front, rain will change over to snow Friday night
with temperatures falling back towards and below freezing. With
precipitation changing over to snow, an additional 0.5-1" of snow is
possible in the western facing slope of the Adirondacks and along
the spine of the northern Greens. Froude numbers suggest unblocked
flow, so any snow that falls Friday night will be over or on the lee
side of the mountains. A brief lake effect band may fluctuate about
the St. Lawrence/Lewis County border which could bring some
additional localized snow up to an inch. As snow compacts and
refreezes on the surface the existing snowpack, the smoother
frictionless icy snowpack could lead to some blowing and drifting
snow Friday night with gusty winds present. While temperatures will
fall from the upper 30s to near 30 in a 4-6 hour span, the
likelihood of any flash freeze remains unlikely as the speed of
the caa does not seem conducive for a faster fall to freezing.
However, given rain and snow melt from the day on Friday, black
ice will be more likely to form Friday night into Saturday
morning with any standing water and melt. Travel Saturday
morning could be slick in spots. Our flow pattern will relax
from being amplified to be more zonal which should support some
clearing with subtle ridging Saturday morning. However, another
transient clipper system will move over the Great Lakes late
Saturday with increasing cloud cover and some snow chances into
late Saturday afternoon/evening in the St. Lawrence Valley.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 1231 PM EST Thursday...Colder air aloft is expected to rush
into northern New York and Vermont following a cold front on Sunday,
likely resulting in dropping temperatures throughout the afternoon.
Our slightly-above- seasonable highs in the upper 20s and 30s are
anticipated at the start of the day, with much of the day
experiencing cooler conditions. The colder air will also be drier
than the pre-existing air mass over the Northeast, and any lingering
scattered showery precipitation in the morning from low pressure
crossing Quebec to our north will diminish into the afternoon.

Any precipitation Sunday will mostly be snow except in parts of the
Champlain Valley near the lake where rain may mix in while
temperatures remain above freezing. Surface winds will also be quite
breezy on Sunday and Sunday night with the passage of the cold front
out of the west with gusts 20-30 knots, higher on summits as a low
level jet blows up to 50-60 knots at the 850mb level. Winds on Lake
Champlain will be especially strong Sunday afternoon into the early
morning hours Monday morning, likely triggering a Lake Wind
Advisory.

The cold front and colder air will result in a cold Sunday night
through Monday night with temperatures falling back below normals as
brief high pressure builds in out of the southeastern US. Again,
will be very brief since our next system looks to arrive Tuesday,
though models disagree on the exact intensity and strength of such a
system as the GFS wants to place surface low pressure and upper
level wave much closer to our area than the ECMWF, which gives us
more of a glancing frontal blow of precipitation. This system should
draw back in milder air through the late week, but still cold enough
and soundings saturated enough to see mostly snow as our
precipitation type.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Through 18Z Friday...A strong frontal system is approaching the
region this afternoon, causing winds to increase out of the south,
warming the region with rainfall on the way tonight. VFR conditions
are widespread and wind gusts 25-30 knots are already occurring in
the channeled Champlain Valley. LLWS is set to continue over the
next 24 hours as a low level jet moves overhead. Winds at 2000 ft
will likely accelerate to 65 to 75 knots out of the south- southwest
this afternoon into tomorrow, which should produce significant LLWS
or severe turbulence that could prove very hazardous to general
aviation.

At the surface, wind gusts of up to 30-45 knots are expected at all
terminals, highest at central and northern VT sites like MPV and EFK
11Z-16Z Friday onwards. Rain accompanying this frontal system is
forecast to arrive around 08Z-11Z and continue through the next 24
hours, bringing with it MVFR ceilings 1000-3000 feet above ground
level. Of all the sites, models are suggesting RUT as the site most
likely to see ceilings 500-1000 feet, though agreement amongst
solutions is minimal. If IFR conditions are to occur, the thinking
is that they will generally be in the form of lowered visibilities
to 1-3 miles 12Z-18Z Friday in moderate rainfall, most likely at
SLK. At this time, confidence is low enough to leave out of the TAF,
but will be reassessed at next TAF package.

Outlook...

Friday Night: Mainly VFR, with areas MVFR possible. Chance SHSN.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Chance SN.
Sunday: Mainly VFR, with local MVFR possible. Chance SHSN.
Sunday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. Slight chance SN.
Tuesday: Mainly VFR, with local MVFR and IFR possible. Likely SN.

&&

.HYDROLOGY...
Sharp rises on streams and rivers are anticipated on Friday
into Friday night associated with warm temperatures, snow melt,
and moderate rainfall. Rainfall of 0.50 to 1.25 is expected with
snow melt adding another 0.75 to 1.25 inches into the river
basins. Given dewpoints will be above freezing during the day
today and tomorrow, efficient snow melt will be likely. Snow
core analysis Tuesday near Mt Mansfield indicated at 3000 feet
snow depths were 53 to 58 inches with 12 to 14 inches of water,
while at 1550 feet snow depths were 22 to 30 inches with 5 to 7
inches of water. The rivers with greatest potential to reach
action stage, given expected rainfall and snow melt are the
Ausable, Mad, Winooski at Essex Junction, and Otter Creek at
Center Rutland on Friday afternoon and evening. Crests on the
Mad and Ausable Rivers will be Friday afternoon, and Otter
Creek and the Winooski cresting closer to Friday evening/early
Saturday morning. Lastly, while any river ice may move, the
threat of ice jams remains low.

&&

.MARINE...
A Lake Wind Advisory is in effect for Lake Champlain through this
evening. Southerly winds ahead an approaching frontal system
will lead to channeling effects on Lake Champlain enhancing wind
and wave conditions. Winds on the broad lake will increase to
20 to 30 knots with gusts as high as 45 to 55 knots, becoming
strongest tonight. Waves will be generally 4 to 6 ft on the
broad lake and 2 to 4 on the northern and southern ice free
portions of the lake. Strong gusts will continue through Friday.

&&

.CLIMATE...
Incoming warmer air and precipitation is presently forecast to
approach daily record values. The most likely date for records
will be Friday December 19th for both daily high temperatures
and precipitation. Below are some of the daily records in
jeopardy of being broken (current forecast at or within 3
degrees of the record).

Record High Temperatures:

December 18:
KBTV: 49/1895
KMPV: 49/1949
KPBG: 49/1967
K1V4: 47/2023


Record Daily Precipitation:

December 18:
KBTV: 0.62/1912
KMPV: 0.35/1998
K1V4: 0.24/1998
KMSS: 0.43/1970
KPBG: 0.17/1970
KSLK: 0.70/1912

&&

.EQUIPMENT...
NOAA Weather Radio station WXM-44, transmitting from Mt.
Ascutney, Vermont, on frequency 162.475 MHz is non-operational
at this time. NWS technicians have diagnosed the problem, but
repairs will likely not be able to occur for quite some time due
to circumstances beyond our control. Therefore, the time of
return to service is currently unknown. The following NOAA
Weather Radio transmitters may be able to provide service during
this outage: WWG 50 from Burke Mtn, VT at 162.425 MHz and WNG
546 from Hanover, NH at 162.525 MHz.

Equipment malfunctions at the Colchester Reef meteorological
station will likely leave it inoperable for an extended period
of time. This site is not serviced by the NWS. Technicians do
not currently have an estimated return to service for this
station. Use extra caution when navigating the broad waters of
Lake Champlain, and please contact us if you observe winds
significantly deviating from the forecast.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Wind Advisory until 1 PM EST Friday for VTZ001>011-016>021.
NY...Wind Advisory until 1 PM EST Friday for NYZ026>031-034-035-087.

&&

$$
SYNOPSIS...Danzig
NEAR TERM...Danzig/Taber
SHORT TERM...Danzig
LONG TERM...Storm
AVIATION...Storm
HYDROLOGY...Taber
MARINE...Team BTV
CLIMATE...Team BTV
EQUIPMENT...Team BTV