074
FXUS61 KBTV 121146
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
746 AM EDT Wed Aug 12 2026
.WHAT HAS CHANGED...
As of 309 AM EDT Wednesday...
No significant changes were made. Isolated to scattered showers
with a few embedded thunderstorms are expected today.
&&
.KEY MESSAGES...
As of 309 AM EDT Wednesday...
1. Isolated to scattered showers are expected this afternoon
with a few thunderstorms mixed in. Chances increase Thursday
as a wave moves through with lingering showers Friday.
2. Tranquil weather on Saturday, then beneficial rain likely
spreads in from the west Sunday afternoon and exits on Monday.
Becoming seasonably warm and dry early next week.
&&
.DISCUSSION...
As of 309 AM EDT Wednesday...
KEY MESSAGE 1: Maintained yesterday`s forecast change of
including some showers and very isolated convection today. Best
chances of thunderstorms lie in the St Lawrence Valley where the
CAPE gradient will be sharpest with around 500J/kg to work with.
Otherwise, temperatures will be similar to yesterday with highs
in the mid/upper 70s to low 80s today and Thursday. Shower and
thunderstorm chances increase Thursday as low pressure moving
through southern Canada pushes a boundary through the region.
Around 500 J/kg of CAPE is projected to be in the region
coincident with the weakening boundary with the strongest
forcing towards the Canadian border(CAMs are highlighting
potential for a bullseye of 1000+J/kg at max heating which may
strafe our northern zones in Vermont - lower likelihood, but
potentially impactful scenario where a couple stronger storms
would be possible). Another trough is anticipated to move
through Friday in broad northwest flow. Showers are mostly
expected, but could see a few rumbles in southern Vermont where
timing will play a roll in convective chances. Should the trough
slow, surface instability will likely build enough for more
showers and storms, but current timing of this wave supports
mainly showers as the wave exists early afternoon. Some breezy
conditions should be anticipated with this trough, especially on
Lake Champlain and the peaks where gusts could approach or
exceed 30 mph. Gusts 15 to 25 mph are probable at lower
elevations away from Lake Champlain.
KEY MESSAGE 2: A mid-level ridge over the southeastern US will
build northward a bit on Saturday, leaving us in northwesterly
flow with dry air and no precipitation chances. This ridge will
breakdown on Sunday, allowing a weak wave of low pressure
originating in the foothills of the Colorado Rockies to zip
eastward and bring us some overrunning/warm frontal type of
rain. There is a slight chance of thunder indicated at this time
Sunday night in much of Vermont, which would only be a factor
if the low pressure system trended stronger and/or tracked
farther north, such that our region got into the system`s warm
sector. Otherwise, a steady soaking rain looks favored, with
current consensus timing from Sunday afternoon through Monday
morning. Probabilities of event total rainfall exceeding 0.5"
currently ranges from about 20% to 40%, tapering off generally
towards the north. among the latest global ensemble scenarios,
some solutions are a little slower to bring rain to an end on
Monday with higher probabilities of rain into Monday evening
than what the current forecast suggests. Given the
uncertainties, the 10-30% chance of showers Monday afternoon
looks reasonable at this time; some of this precipitation could
be orographic, post-frontal showers.
Following this system it appears a ridge of high pressure may build
in, which would provide us with generally quiet weather for Tuesday.
There are weak signals for perhaps a terrain-driven shower in the
Adirondacks or off of a lake breeze interface, which would make
sense given a typical summertime heating scenario with lack of other
forcing mechanisms for precipitation.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Through 12Z Thursday...Dense fog at SLK will dissipate within
the next hour leaving VFR conditions at all terminals through at
least 18Z. Clusters of showers with a couple of thunderstorms
are expected to develop in southern Canada this afternoon or
early evening and move southeastward across portions of northern
New York and Vermont. Have only used prevailing showers/MVFR
conditions at MSS where stronger consensus of a direct hit
exists, in which brief IFR conditions would also occur. Other
sites fit more in the chance category for showers and PROB30s
were used. Additional showers after 00Z are expected but beyond
the timeframe to indicate in the TAF.
Aside from a thunderstorm or stronger shower winds will remain
light; during the daytime, generally expect west/northwest
winds, except terrain driven in the Champlain Valley (SE at PBG,
N-NW at BTV). With these light winds, nocturnal fog
redevelopment at SLK is anticipated but could be affected by coverage
and timing of these showers lingering into the overnight hours.
Evening precipitation would also aid in fog formation at MSS,
and perhaps other sites that are less likely to see appreciable
rain such as RUT, MPV, and EFK.
Outlook...
Thursday: VFR. Chance SHRA, Chance TSRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. Slight chance SHRA.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Boyd
DISCUSSION...Kutikoff/Boyd
AVIATION...Kutikoff
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