Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 261129
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
729 AM EDT Tue Mar 26 2024

.SYNOPSIS...
Ahead of a weak frontal passage mild temperatures are expected
today, and areas of drizzle tonight with scattered rain showers
following for Wednesday. Mild temperatures continue for the
remainder of the week with additional chances for showers Thursday,
possibly ending as a light coating of snow. Cool and dry weather is
expected for the upcoming weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 729 AM EDT Tuesday...Update to the forecast this morning
to adjust cloud cover as low clouds advancing on southeast flow
have quickly spread across Rutland/Orange/Windsor counties. This
northward advancement should continue east of the Greens, but
it`s difficult to tell if the flow will be strong enough to push
them up over the central/northern Greens enough to impact the
high temp forecast. If clouds do in fact make it over the
ridgeline, temps in the northern Champlain Valley may end up a
good 10 degrees cooler than forecast. We`ll monitor over the
next few hours and adjust accordingly for the mid-morning
update.

Previous Discussion...Outside of some light patchy drizzle
across the southern mountains, today`s forecast features
increasing clouds and mild temperatures ahead of a frontal
passage tonight. Increasing southeasterly flow will filter in
low clouds across eastern Vermont this morning, while mid/high
clouds approach western/northern areas from the west. A sharp
gradient in temperatures is expected with low clouds keeping
temperatures in the 40s east of the Green Mountain spine, while
westward, 925mb temps rising to +8-10C will support highs well
into the 50s with some low 60s possible in the St. Lawrence
Valley.

For tonight, chances for showers increases especially across
northern New York as low pressure tracking well west of the region
through the central Great Lakes will advance an occluded front
toward the region. Additional chances for showers follow for
Wednesday across the entire region as the front stalls to our west
and several waves of upper level energy ride ahead of the boundary
through the forecast area. Precipitation should be scattered in
nature, with limited QPF expected. A mild night is expected tonight
west of the Green Mountains with lows mainly in the 40s, while
eastward cooler temps will remain with lows in the 30s supporting
the idea of the potential for some patchy freezing drizzle. Warmer
temps eventually develop across the entire region Wednesday
afternoon with widespread highs in the upper 40s to lower 60s.

It should be noted that with a deep snowpack across the region and
warm air moving over said snowpack, there could be areas of fog
tonight through Wednesday where winds decouple. Confidence is low
right now as dewpoints remain in question, so have left out of the
forecast for now.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 414 AM EDT Tuesday...On Wednesday night, a decaying cold front
will shift east into northern New York. There`s some question on
whether it washes out entirely before reaching out area or not. If
it does make it, there should be a few showers along the boundary.
If it does not make it, it is hard to say because there`s even
question on whether there is still some positive thickness advection
across eastern Vermont. I suppose this would define the airmass as
"junky" with spotty showers streaming northeast along the thermal
gradient that remains along the washed up front. Lingering warm air
means temperatures will likely remain above freezing ranging in the
mid 30s to lower 40s.

During the day, an embedded shortwave within the longwave troughing
across the eastern CONUS, in conjunction with some convective
activity along the coastline, will send a surge of moisture
northward. Where that thermal gradient is will play a large part in
whether it crosses here. Forecast guidance is split between dry or
very wet, with only a few middle ground solutions in some ensembles.
What we`ll have to watch is another embedded shortwave a bit closer
to the upper low that digs southeast about the same time, which will
advect dry air into the region. This will result in a very sharp
precipitation/PoP gradient. If the northern stream system is
progressive, most precipitation should remain well east. There`s
quite a bit of spread with this. The forecast employs a technique
often used this cold season with these high uncertainty events. It`s
a blend of blends, and future updates will follow statistical trends
where it needs to be taken. High temperatures in the 40s should
support snowmelt across the region as well. If there`s a westward
shift with the moisture plume, then we`ll have to keep a close watch
on how much liquid is getting into our rivers. Some probabilistic
guidance indicates sharp rises, potentially near minor flooding at
Otter Creek at Center Rutland and the Mad River at Moretown.

Overnight, the system appears most likely to head off shore. Again,
there remains a few uncertainties. The main one being whether there
is any level of phasing between the two systems. If they do
interact, then precipitation will be slower to shift east, and with
cold air and falling heights, a transition to snow would then take
place sometime near or after sunset. This possibility would mainly
be confined to eastern Vermont based on present information.
Temperatures overnight will sink into the 20s to lower 30s, Thursday
night.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
As of 414 AM EDT Tuesday...On Friday, we`ll be in the subsidence side
behind the offshore system that will have developed into a deep,
stacked low. Cool northwest winds will result in temperatures
relatively close to seasonal normals, which are mid 40s and
overnight lows in the 20s. A shortwave blitzes east in zonal,
channeled flow aloft on Sunday. The placement of it is widely
variable at this stage, but if it comes through overnight, it could
support some snow. If it comes through in the day, then it`d be
elevation dependent rain and snow. By next Monday, conditions appear
likely to favor dry conditions, with temperatures trending back
upwards.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Through 12Z Wednesday...MVFR ceiling are quickly advancing
through central/southern Vermont and the expectation for the
remainder of the day is that this northward advancement will
continue reaching KMPV within the next 2 hours, KEFK/KBTV/KPBG
by 19-21Z, and eventually KSLK/KMSS by 22-02Z. Further lowering
of ceiling is expected after 00Z with most sites IFR by 06Z.
Winds will generally be <8kts from the SE except locally NE at
KMSS through much of the period, with areas of LLWS after 06Z.

Outlook...

Wednesday: Mainly VFR, with local IFR possible. Chance SHRA.
Wednesday Night: MVFR/IFR conditions possible. Chance SHRA.
Thursday: MVFR/IFR conditions possible. Chance SHRA.
Thursday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, Chance SHSN.
Friday: VFR. Slight chance SHRA.
Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday: Mainly VFR, with areas MVFR possible. Slight chance
SHRA.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Lahiff
SHORT TERM...Haynes
LONG TERM...Haynes
AVIATION...Lahiff


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