981
FXUS61 KBTV 151117
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
717 AM EDT Wed Apr 15 2026

.WHAT HAS CHANGED...
As of 338 AM EDT Wednesday...

Confidence in potentially severe weather has increased across
portions of southern Vermont for Thursday. Fog is also likely
tonight as a boundary remains over the region.

&&

.KEY MESSAGES...
As of 338 AM EDT Wednesday...

1. Light showers and isolated rumbles of thunder expected today
trending towards more drizzle and fog by tonight with a boundary
remaining draped over the region.

2. Additional rounds of showers with heightened thunderstorm
chances expected Thursday into Friday across southern Vermont
as a stronger frontal system rides along our quasi stationary
boundary.

3. Another storm system is expected to bring rainy and windy
weather to the region Saturday evening through Sunday, with showers
potentially switching over to snow on Monday as cold air briefly
returns.

&&

.DISCUSSION...
As of 338 AM EDT Wednesday...

KEY MESSAGE 1: Widespread low clouds and patchy fog remain across most
of the region with pooling moisture along a quasi stationary
boundary draped across our region. Any fog is expected to lift with
sunrise as light southerly flow nudges the boundary slightly north
for this afternoon. Satellite shows widespread convection associated
with merging MCSs in the Upper Midwest to the eastern Great Lakes,
as thunderstorms continue to move east along a quasi stationary
boundary draped across the Great Lakes into the Northeast. Our
shortwave today is currently positioned across the lower Michigan
peninsula with an MCS moving east into Lake Erie. CAMs show this
area of convection weakening as it approaches the St. Lawrence
Valley this morning. What remains of the MCS as it enters our region
will likely just be some light to moderate showers with an isolated
rumble of thunder, mainly in the St. Lawrence Valley this morning,
with shower activity diminishing as it moves east and becomes cutoff
by its cold pool. Cooler air from this cold pool near the
International Border will keep the northern areas of the region
cooler today with highs in the low to mid 50s, where locations south
like Springfield and Rutland, Vermont may warm into the 70s. Unlike
yesterday, there is better confidence in cloud cover and convective
inhibition lingering through most of the day from this approaching
MCS. The cold pool should remain over the region today limiting the
potential for severe weather or any widespread thunderstorms.
However, south of the boundary into Rutland/Windsor Counties, any
clearing today may allow for some isolated thunderstorm development,
though these storms should remain sub severe and weak, with better
instability south of our region. Light showers will continue into
this evening with weak forcing, with perhaps some mid level drying
from upper level divergence associated with an approaching low level
jet for Thursday. This drying will be associated with a strong
inversion tonight which will likely lead to widespread drizzle and
some patchy fog as temperatures cool, but surface moisture remains
ample. Lows tonight will be similar to last night with values in the
mid 40s to mid 50s.

KEY MESSAGE 2: A shortwave currently over the Central Plains will track
across the Great Lakes into our region Thursday with increasing
showers and embedded thunderstorms. This area of energy will ride
along our nearly stationary boundary that will remain parked over
the region through the end of the week. The latest SPC day2 outlook
shows a Slight Risk (2 out of 5) for western Rutland County in
Vermont, and southern Essex County in NY, with a Marginal Risk (1
out of 5) for portions of the northern Adirondacks and central and
southern Vermont on Thursday. The main threat with any thunderstorms
Thursday look to be damaging wind gusts and some isolated large hail.

As with the recent days, there is little change in the overall
synoptic pattern with a strong ridge across the southeast leading to
several rounds of showers and thunderstorms into the weekend. A
shortwave on Thursday will likely be preceded by a decaying MCS as
has been the theme the last few days. Convective blowoff through the
day will help to keep instability at bay for the better part of
Thursday before some clearing can work in for the afternoon/evening.
A weak sfc low will track northeast along the St. Lawrence Valley
with a lifting warm front during Thursday morning. It will be
difficult to determine how much cloud cover remains into the
afternoon as to how much instability can develop. The HRRR and HREF
appear to be the most aggressive across southern Vermont with the
HREF denoting 50-70% chance for > 500 J/kg of sfc CAPE, and 30-40%
for > 1000 J/kg, which for mid April is pretty good. Additionally,
the low level jet associated with the sfc low will be better located
with the highest CAPE as compared to Tuesday with a colocated
maximum of 0 to 6 km shear up to 50 kts, which would support
thunderstorm activity. The NAM3 is more muddy with broken cells and
stratiform mixed in which would limit any discrete cell potential,
which does exist in the HRRR 00Z run. Given the presence of the
boundary, the best chances for any severe weather would be across
Rutland/Windsor counties with temperatures potentially into the mid
70s. Areas north of the boundary could remain in the low to mid 60s
depending on the precipitation shield and cloud cover, which will be
hard to determine as the boundary fluctuates. Pwat values will be
near 1 to 1.3" which would support some localized heavy downpours,
and combined with elevation snowmelt, some sharp rises on
central/northern waterways are likely through Friday. However, no
flooding is expected, but high flows will need to be watched
depending on any repeated thunderstorm activity. The main threat
with any storms would be damaging winds and isolated large hail,
though, some rotating storms cannot be ruled out with curved
hodographs and > 250 m2/s2 0 to 3 SRH values in southern Vermont.

A similar pattern setup on Friday will lead to additional shower
and thunderstorm chances. A sfc low will track across the
region, with some better forcing underneath the center of the
low across the Adirondacks and central and southern Vermont.
Thunderstorm chances will be maximized in the late morning and
early afternoon with surface instability likely from another
decaying MCS. However, the instability will be competing with a
drying mid to upper level as a nose of high pressure will try to
work in for Friday afternoon. There is still some timing
differences between global models which will play a role in
where any thunderstorm activity will setup. CAMs will be in
range in the next forecast package to provide some better
guidance.

KEY MESSAGE 3: Surface low pressure is expected to cross Ontario into
Quebec on Saturday, with an upper level trough trailing slightly
behind it. Southerly winds will increase as gradients tighten over
northern New York and Vermont and as a strong low level jet streak
approaches the area from the west. This southerly flow will advect
in plenty of warmth by Saturday afternoon with highs reaching into
the upper 60s and lower 70s, which is 10-15 degrees above seasonal
normals for this time of year. The south/southwest orientation of
the low level jet will favor gusty winds over the St. Lawrence
Valley, off the northern slopes of the Adirondacks, and channeled up
the northern Champlain Valley, where gusts in the range of 20 to 30+
knots are possible late Saturday afternoon and into the overnight.
Precipitation chances will also increase late Saturday afternoon and
evening, with widespread soaking rainfall likely lingering into
Sunday afternoon and evening as well. An associated cold frontal
boundary is forecast to cross the forecast area early enough Sunday
morning to limit destabilization and thunderstorm potential. Model
blend precipitation projections continue indicate we could get
around a quarter of an inch of precip in 24 hours, but not likely
much more than that. Colder air rushing in behind the front Sunday
will make it tough for most spots to reach above the 50 during the
afternoon before falling into the 20s and lower 30s Sunday night.
Due to this dramatic temperature drop towards freezing, there is the
potential for lingering rain showers to change over to snow showers
Sunday night, starting first on mountaintops and lowering in
elevation from there. By the time the cold air reaches the wider
valley floors early Monday morning, probability of precipitation
will be only about 20-40%. Highs Monday will likely only reach the
mid 30s to lower 40s. High pressure takes over early next week to
recover temperatures slightly, then model consensus dwindles beyond
that.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Through 12Z Thursday...Widespread low clouds (cigs 200-1400 feet
above ground level) and patchy fog (visibilities 1/4 to 6
miles) remain across most of the region with pooling moisture
along a stationary frontal boundary draped across our region.
Fog and low clouds are expected to lift following sunrise as
light southerly flow nudges the boundary slightly north for this
afternoon. Widespread MVFR or VFR conditions are anticipated by
around 15Z-16Z Wednesday. Light showers and isolated rumbles of
thunder are expected today trending towards more drizzle and
fog by tonight with a boundary remaining draped over the region.
Most likely time period of showers will be 15Z through 21Z
Wednesday. Visibilities may briefly lower to below 4 miles in
these showers/storms, but confidence is not high on the exact
timing and location of this lower vis today. By 00Z-06Z (MSS a
little earlier) Thursday, we should see a return to widespread
IFR ceilings and potentially IFR visibilities tonight, similar
to what was observed last night as mist and drizzle get trapped
under an atmospheric inversion. Surface winds over the next 24
hours will be light and highly variable, with some
southwesterly to southerly component this afternoon. MSS could
have an overall northeasterly flow instead, at times 10-15 knots
this afternoon. Some LLWS is also expected over the Adirondacks
as southwest to west winds at 2000 feet increase around 15Z
Wednesday through 02Z Thursday at SLK.

Outlook...

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

&&

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

&&

$$

WHAT HAS CHANGED...Danzig
DISCUSSION...Danzig/Storm
AVIATION...Storm