559
FXUS61 KBTV 081802
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
102 PM EST Wed Jan 8 2025

.SYNOPSIS...
Intervals of snow showers and cold, gusty winds are expected into
Thursday. Accumulating snow or blowing and drifting snow could
result in areas of hazardous travel through Thursday, especially
along northwest facing slopes and high peaks. On Friday, a break
from snow and wind is expected along with moderating temperatures.
Some light snow will impact the region Saturday followed by cool
temperatures.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1227 PM EST Wednesday...A cold and blustery day is on tap
with intervals of snow showers. Water vapor imagery shows s/w
energy approaching the International Border with associated mid
lvl moisture with some cooling cloud tops on the IR satl. This
energy combined with upslope flow and continued low level cold
air advection wl help to squeeze out additional moisture with
continued snow showers. Sounding analysis shows subcritical with
Froude numbers in the 0.50-1.0, with values increasing toward
1.0 for several hours this aftn, before becoming
subcritical/blocked toward 00z again, as inversion lowers below
summit level. This general idea supports greatest
snowfall/highest pops/qpf near/over the central/northern Greens
and into parts of the northern Dacks, which is covered well in
crnt fcst. As slightly deeper moisture and better lift arrive
btwn 15z-21z today, expect snow growth to improve with better
flake size, especially in upslope areas. Additional snowfall
today mostly in the 1 to 3 inch range with localized 3 to 5
inches in the trrn. Temps wl struggle under caa on brisk
northwest winds with highs only in the single digits to lower
teens most locations. Wind chill values -5F to -15F as northwest
winds are 10 to 20 gusts 20 to 35 mph. Soundings show a little
lighter winds today, compared to yesterday.

Previous discussion below...

Winter Weather Advisory has been extended to 7 PM Thursday and
added northern St. Lawrence County including areas like Massena.
An additional 3 to 9 inches will be likely through Thursday
over the northern Greens and along Route 11 in New York.

There`s going to be little change to the weather over the next
couple days. It made sense to extend the Advisory given that under
cyclonic flow, we will continue to observe fluctuations in snow
shower activity. We`re in a bit of a low point in activity this
morning, partly due to how cold we are. About noon, we should see
coverage gradually increase behind an upper low sliding south. With
flow unblocked, this wave of snow showers should slide all the way
south. Then behind this impulse, flow will become increasingly
blocked with multiple DGZs that are saturated or even
supersaturated. Expecting some very fluffy snow, especially given
the 25 to 35:1 snow ratios observed yesterday. By Thursday
afternoon, dry air will start to shift into the region, although
another weaker upper trough will pinwheel southwards and spark
additional activity. Without the deep moisture, we will probably
lose on the fluff factor, but areas north of I-89 in Vermont will
likely add another 1 to 6 inches, while the northern Greens will
range from 4 to 8 inches. Along Route 11 in New York and down to
Saranac Lake, an additional 2 to 8 inches is likely. The way
moisture angles in, it looks like that the northern St. Lawrence
Valley will also do quite will with 2 to 6 inches possible.

Conditions will remain gusty through Thursday night. Especially for
today, winds at the top of the mixed layer increase to 35 to 40
knots, which would support the potential for gusts ranging from 30
to 40 mph today, especially along eastern slopes of the southern
Greens and in some of the eastern foothills of the Adirondacks. For
today, this means very cold wind chills ranging from 5 to 15 below
through at least Thursday morning. As we head into Thursday, the
inversion layer will sink quite low to the ground. Winds could still
remain steady due to increasing pressure gradients as a surface high
starts to nose in, but Thursday will be in the 15 to 25 mph gust
range.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
As of 459 AM EST Wednesday...Snow showers will taper off in the
northern Greens and northeast Kingdom Thursday night as deeper
moisture dissipates, such that only very shallow clouds remain.
Cold low level air will still be present so any additional snow
still will be on the dry/light side, but with such little
saturation aloft and lack of upward motion in the DGZ, snow
ratio may be limited to 15:1 or so. Up to a couple more inches
of snow may fall during this period.

Dry and seasonably cold conditions can be expected on Friday as
anticyclonic flow finally slides in from the west. The unrelenting
pressure gradient will subside resulting in relatively light
northwesterly winds at most in the 10 to 15 MPH range. Lingering low
inversion heights and limited heating will keep skies cloudy
potentially into a good portion of the day, especially in northern
Vermont where thicker clouds are expected to be present prior to
sunrise. Morning temperatures look potentially frigid in western
portions of northern New York where decoupling may occur above a
fresh snowpack, while most locations remain close to steady tomorrow
night with lows dropping back into the teens. High temperatures will
then rebound decently, ending up largely about five degrees below
normal, with highs mainly ranging from the upper teens to upper
twenties.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
As of 459 AM EST Wednesday...Looking at global teleconnection
patterns, we will likely have a change from negative to weakly
positive Arctic Oscillation (AO) during this period. Recent
negative AO along with a positive Pacific-North American (PNA)
index have supported persistent cold conditions over the region.
The upcoming stretch does not seem to have a significant PNA
signal, but overall the loss of Greenland blocking is probably
going to contribute to a coastal storm going out to see well to
the south of the 40N 70W benchmark on Saturday. For our region,
a shot of light snow associated with some minor isentropic lift
and Lake Ontario moisture ahead of a broad trough is likely by
early Saturday with snow amounts dwindling eastward through the
Adirondacks. Then fairly quiet weather is favored through the
remainder of the weekend with temperatures near or slightly
below normal.

Precipitation chances early next week become rather uncertain as a
piece of a polar vortex becomes centered somewhere near the western
Great Lakes region. The flow pattern out ahead of this system
supports a lot of westerly flow as a large trough gets carved out
across the northeastern US. So while no storm system is expected
through this period for our area, it is hard to rule out some snow
shower activity, especially as the lakes upstream likely remain
mostly ice-free. The best forcing for widespread precipitation may
pass to our south and west during this period, but we`ll watch for
any trends in the coming days.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Through 18Z Thursday...A wide range of changeable conditions
crntly from VFR at PBG/RUT to IFR at MSS/SLK and MVFR at
EFK/BTV/MPV with intervals of snow showers and areas of blowing
snow. As better moisture and lift arrive from north to south
across our taf sites by 21z this afternoon, expect a trend
toward IFR/MVFR at most sites. Highest confidence of prevailing
IFR or lower at SLK/EFK and MSS with intervals of IFR possible
at BTV/MPV and RUT, while PBG stays mostly MVFR/VFR thru the
period. The combination of snow showers, blowing snow and haze
will result in sfc visibilities between 1-3SM while CIGS hold
mostly in the MVFR. As moisture decreases toward 06z Thursday,
expect conditions to slowly improve to MVFR/VFR. Blustery winds
continue from the west/northwest at 10 to 20 knots with
localized gusts 20 to 30 knots, especially at MPV thru the
period. Areas of wind shear and turbulence likely given the
strong low level wind fields.

Outlook...

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

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Weather Advisory until 7 PM EST Thursday for VTZ002-006-
     016-017.
NY...Winter Weather Advisory until 7 PM EST Thursday for NYZ026-027-
     029>031.

&&

$$
SYNOPSIS...Haynes
NEAR TERM...Haynes/Taber
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Taber