115
FXUS61 KBTV 030810
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
310 AM EST Mon Feb 3 2025
.SYNOPSIS...
A break in precipitation will be observed through early this
afternoon before snow and rain return to the region as a cold front
approaches from the northwest. Widespread snowfall, mixed with rain
in the Connecticut and Champlain Valleys in the afternoon, will
continue into early Tuesday morning before finally tapering off.
Quieter weather is in store for Tuesday and Wednesday as high
pressure begins to build overhead. Another low pressure system is
expected to bring a mix of rain, snow, sleet, and possibly freezing
rain to the region on Thursday.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 309 AM EST Monday...Light snow is quickly exiting the region
this morning with widespread 1-2 inches of fluffy snow falling
during the evening and overnight hours. There is a slight chance we
could see a little freezing drizzle across the Adirondacks and St.
Lawrence Valley this morning as the snow growth layer dries out. If
the precipitation continues to shift eastward as it has been over
the past few hours, we will likely avoid the freezing drizzle
potential so we will be keeping a close eye on it. A pronounced dry
slot will move over the region by 12Z which will lead to a period of
dry weather from 8 AM through around 2 PM before precipitation
associated with a cold front approaches from the west. Precipitation
type is going to be a bit tricky given boundary layer temperatures
warming above freezing in most, if not all, locations this
afternoon. Due to the dry slot during the morning an early afternoon
hours, we will likely hold onto some dry air in the low levels ahead
of the onset of precipitation. This should allow for wet-bulbing to
occur and quickly cool temperatures off 1-3 degrees. In addition,
precipitation is expected to largely be anafrontal (on the backside
of the front, not ahead) which means cold advection aloft will
already be occurring as precipitation begins. These factors are
expected to allow precipitation be mainly snow but will likely be
mixed with rain for an hour or so before changing over to all snow.
Model soundings show that the thermal profiles will largely be
isothermal within the lowest 2000 feet or so which will keep snow
ratios in the 5:1 to 8:1 range through much of the afternoon and
early evening before snow ratios increase closer to climatological
normals overnight. Much of northern New York can expected a good 1-3
inches of wet snow followed by 1-3 inches of fluffier snow. For
Vermont, the highest snow totals will be near the International
Border where precipitation type will likely never change over to
range. With all that being said, we expected 3-6 inches across St.
Lawrence and Franklin Counties in Vermont, and 3-6 inches across the
northern tier of Vermont. Elsewhere 1-4 inches of snow is expected
with lesser amounts in the Champlain and southern Connecticut River
Valley given the warmer boundary temperatures (more mix of rain).
Precipitation will largely taper off by midnight but convergent
northwesterly flow will likely keep snow showers ongoing along the
western slopes of the Adirondacks and northwestern slopes of the
Green Mountains into Tuesday afternoon.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
As of 309 AM EST Monday...Quiet weather conditions are expected for
Wednesday. The overnight into morning hours will begin cold, due to
strong radiational cooling underneath a surface high greater than
1030mb and relatively fresh snow. Single digits on either side of
zero are likely. Light winds and relatively clear skies beneath the
dome of high pressure should allow us to warm us up to a seasonably
cold, but pleasant afternoon in the teens to mid 20s with light
winds.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 309 AM EST Monday...Dry weather is expected for Wednesday night
with another cold night with readings near 0 or just below zero
across cold spots up to lower 10s near Lake Champlain. Precipitation
is expected to arrive Thursday from a pair of shortwaves. Amongst
various model suites, there are two main scenarios that could evolve
on Thursday. Either way, precipitation will begin initially with a
wave of snow lifting north associated with a weak shortwave. A
much larger system will race eastward and overtake it, which
will bring warmer and drier air as it slides off to our north.
One potential scenario is that the smaller system spawns a strong
enough coastal low to maintain cold air across the region. However,
dry air from the incoming larger system coming in from the Great
Lakes would result in an unsaturated dendritic growth layer, and
this would likely shift things into freezing drizzle or rain since
there is still modest forcing around with PWATs 125-150% of normal.
The GFS is outputting "snow", but soundings suggest otherwise for
much of Thursday afternoon through about midnight. However, if it
can warm above freezing, then this may end up being a concern mainly
for unpaved surfaced due to the recent cold.
The second potential scenario is that the smaller upper shortwave
doesn`t spawn a coastal low fast enough before the larger system
races in from the Great Lakes and warm air quickly overtakes it.
This would bring the classic but disappointing transition of snow to
sleet to freezing rain to finally rain. With a stronger push of warm
advection, this would likely lead to a bit more QPF.
The current forecast sent out attempts to thread these two ideas
together. Either way, this system will be fast. The bulk of
precipitation will be out of here soon after midnight, but there
will be a orographic snow showers along northwest mountain slopes.
The air will remain rather dry, though, and it appears unlikely to
add much. Seasonably cold conditions will linger for a few days with
Saturday mainly dry while surface high pressure builds overhead. The
next system comes next Sunday, and it looks like it could follow a
similar trajectory to Thursday`s system, but it will be packing more
moisture. So we will have to see how things evolve.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...Light snow continues at all terminals
across the North Country this morning with MVFR to IFR
conditions being observed. Snow will taper off over the next few
hours from west to to east which will allow for some gradual
improvement at terminals. However, MVFR conditions look locked
in through around 12Z before some drier air works into the
region and VFR conditions begin to prevail. Gusty winds will
develop after 12Z in response to the drier air with most
terminals gusting upward of 20 to 22 knots from the south. A
period of light to moderate snow is expected towards the end of
the TAF period with IFR to VLIFR conditions expected from 00Z
onwards.
Outlook...
Tuesday: Mainly VFR, with local MVFR possible. Windy with gusts
to 30 kt. Slight chance SHSN.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. Chance SN, Slight chance SHSN.
Thursday: MVFR/IFR conditions possible. Definite SN, Chance RA,
Slight chance FZRA.
Thursday Night: Mainly MVFR, with local IFR possible. Chance
SHSN.
Friday: Mainly VFR, with local MVFR possible. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Weather Advisory from 1 PM this afternoon to 7 AM EST
Tuesday for VTZ003-004-006-016.
NY...Winter Weather Advisory from 1 PM this afternoon to 7 AM EST
Tuesday for NYZ026-027-029-030.
&&
$$
SYNOPSIS...Clay
NEAR TERM...Clay
SHORT TERM...Haynes
LONG TERM...Haynes
AVIATION...Clay
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