705
FXUS61 KBTV 181812
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
212 PM EDT Mon Aug 18 2025

.SYNOPSIS...
Dry and cool conditions will continue through Tuesday. Light
rain will spread into parts of the area Tuesday night and
Wednesday, then more dry conditions and a warming trend is
expected late in the week. More significant rainfall may occur
over the weekend associated with a large frontal system.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 149 PM EDT Monday...The coolest air mass we`ve had since
early June is in place today, which will result in another
chilly night. Crisp air with dew points this afternoon near 40
degrees makes it unlikely that temperatures overnight will fall
to their crossover temperatures. Accordingly, while we saw
valley fog develop last night, it is unlikely tonight as our air
mass gradually modifies. Mid-level heights are building and
cool air advection diminishing as the pressure gradient weakens
through tonight. Cirrus and cirrocumulus clouds will continue to
arc southeastward through the region due to northwesterly flow
aloft transporting these clouds from an upper level system
currently over Wisconsin. This will be the lead wave that will
eventually bring clouds and rain chances to our area tomorrow
night, and a trend towards gradually lowering cloud heights
should proceed through the day tomorrow as skies trend overcast.

The associated Canadian high pressure system bringing us this cool,
crisp air will drift southeastward tonight into Maine, setting up an
overrunning type of setup for Tuesday night as a surface trough sets
up right along the International Border; winds to the south/east of
the boundary will become southerly or southeasterly tomorrow while
winds right along the St. Lawrence Valley run down valley from the
northeast. Temperatures will be near normal, or several degrees
warmer than today, with modest warm air advection in the 850-925
millibar layer.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 149 PM EDT Monday...A pair of upper level waves, one
moving eastward and another diving southeastward across the
Great Lakes, will move into the region during this time frame,
helping to generate abundant cloud cover for our region Tuesday
night into Wednesday. The first wave will help blossom showers
over northern New York tomorrow night, with precipitation
potentially shifting southeastward over several hours. The
second of these waves is more likely to force precipitation over
the region during the day on Wednesday, probably focused
farther north. Combined, would expect at least some rain is
certain in our region, but similar to a cold season event, there
is large uncertainty to exactly where and when the bulk of the
precipitation will occur. There will probably be a pretty narrow
corridor that sees much of the rain, with only sporadic and
light rain elsewhere.

The latest model guidance has shown a southward shift for much of
this swath of rain, which could benefit dry areas over southern St.
Lawrence County region eastward into the Adirondacks and central and
southern Vermont. Run-to-run variations are quite large for
individual models, with some even suggesting precipitation shrivels
up, as remnant convective activity upstream dies off with lack of
instability and limited surface convergence/frontogenesis to support
rain in an otherwise dry low level environment in place. Hence,
while we have increased PoPs substantially in south-central Vermont
with the latest forecast similar to areas farther north/west, have
kept values below 60% until the National Blend of Models shows more
more statistical confidence in rain over this area. Would suggest
not paying attention to specific QPF/rainfall amounts at this stage
given low predictability, but generally think a swath of at
least a county width could end up seeing 0.5" of rain through
Wednesday evening given potential long duration of light
rainfall.

Temperatures will be highly dependent on the rainfall pattern, but
are favored to be cooler than tomorrow. The current high and hourly
temperature forecast would be roughly the warmest potential values,
where a wetter/cloudier midday scenario would hold temperatures
substantially cooler given the expected wet bulb cooling/moist and
cool air mass. Temperatures could struggle to warm through the 60s.
The experimental NBM 5.0 hourly probabilistic temperatures show
this uncertainty well with afternoon interquartile ranges of
eight degrees, or twice that of most days such as tomorrow or
Thursday. Winds, especially early in the day and at our mountain
summits, could be breezy with a shallow south/southeasterly
jet; this configuration also should favor some 20-25 knots winds
on the broad waters of Lake Champlain.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 200 PM EDT Monday...Temperatures are strongly favored to
be warming late week before the next system brings chances of
showers and thunderstorms Saturday into Sunday. As such, near
average temperatures are projected in the mid/upper 70s for
Thursday warming into the 80s to near 90s degrees(for a few
locations) by Saturday. The weekend pattern is leaning towards
having a broad, mature upper low tracking across northern
Canada with it`s surface and low level troughs moving piece-meal
through the North Country. While precipitation chances will
sharply rise, strength of forcing remains suspect and will be
dependent on how phased low level features are with upper level
support; QPF amounts remain nebulous, but there stands a decent
chance for a swath of greater than 0.5" somewhere across
northern New York and/or Vermont. Northwest flow should set up
behind the system with cooling temperatures early next week with
some additional light showers possible if the upper low lingers.


&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...Northerly flow today will taper after 21Z
becoming light overnight. Fog chances overnight are marginal at
SLK and MPV given crossover temperatures in the 30s and
projected low temperatures around 40 degrees. Still, it is worth
a mention of at least patchy fog at SLK with slightly better
odds of IFR at MPV in the 07-12Z time frame. Otherwise, VFR
conditions will prevail with flow becoming light out of the
south after 14Z.

Outlook...

Tuesday Night: VFR. Chance SHRA.
Wednesday: Mainly VFR, with areas MVFR possible. Chance SHRA,
Slight chance TSRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Thursday: VFR. Slight chance SHRA.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.

&&

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

&&

$$
SYNOPSIS...Kutikoff
NEAR TERM...Kutikoff
SHORT TERM...Kutikoff
LONG TERM...Boyd
AVIATION...Boyd