St. Johnsbury, Vermont 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

127
FXUS61 KBTV 280618
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
218 AM EDT Sat Jun 28 2025

.SYNOPSIS...
Several rounds of showers with embedded thunderstorms will be
possible throughout the day today. A cold front will swing through
the region this afternoon and evening which will bring an end to our
rain chances with increasing sunshine and seasonal weather expected
on Sunday. A significant warm up is expected Monday as highs climb
into the mid 80s to lower 90s but these temperatures will be short-
lived as another cold front moves through the region on Tuesday.
Several round of rain and thunderstorms will be possible late Monday
and again on Tuesday.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 215 AM EDT Saturday...It`s been an interesting evening across
the North Country early this morning as we`ve seen gusty winds up to
45 mph impact the northern Champlain Valley. The pressure gradient
continues to tighten as an area of low pressure deepens to our west
but the culprit for these gusty winds is a low level jet that`s
currently moving overhead. Most places remain decoupled but places
within the Champlain Valley have been able to overcome a weak
surface inversion to help mix down these stronger winds just off the
deck. In addition, we`ve seen an impressive intrusion of dry air
within the Champlain Valley which is counter intuitive to what we`ve
been expecting. There is a pronounced dry layer accompanying the
strong winds above the surface and the gusty winds within the valley
have been able to bring the drier air down to the surface. For
example, at 1:30 AM, the dewpoint in Burlington and surrounding
sites have dropped between 42 and 44 degrees while we are seeing
dewpoints in the mid 50s in Vermont and the lower 60s across
portions of Northern New York. While we`ve seen an impressive
theta-e ridge build overhead, this pocket of low level drying has
helped to prevent the shower activity from spreading southward out
of Canada. These gusty southerly winds will likely continue through
at least 9 AM and possibly as late as noon before the warm front
moves northward and a more stable warm nose begins to overspread the
Champlain Valley.

As has been expected for the last day or so, the main focus on
precipitation thus far has been centered well north of the
International Border. We had a round of showers yesterday evening
that dropped a half to three quarters of an inch of rain but it has
been generally dry thus far. The latest surface analysis shows that
the main warm front remains south of the region and will continue to
lift north as we head into the afternoon hours before a cold front
sweeps through the region. The latest guidance shows this warm front
lifting as far north as Addison and Orange counties before the cold
front overtakes it by mid-afternoon. A narrow warm sector will
develop across the southern half of Vermont and maybe into the
northern Adirondacks depending on frontal timing which may give way
to a few stronger thunderstorms this afternoon. Any thunderstorms
this afternoon will be heavy rainers as they will be in an
environment highlighted by high PWATs and deep warm cloud depths but
the progressive nature of the cold front will quickly push storms
eastward with little to no chances of training thunderstorms. An
abrupt end to rainfall is expected this evening behind the cold
front. Given the latest guidance, rainfall amounts have been lowered
further which continues to diminish any flood threat across the
region.

Sunday will be a much nicer day across the region as surface high
pressure build across the Northeast with some minor mid-level height
rises. It`ll likely take some time to scour out the low level
moisture Sunday morning so we`ll start off cloudy but we shouldn`t
have any problems breaking out into sunshine Sunday afternoon. High
temperatures will be around seasonal normals with highs in the mid
70s to lower 80s with comfortable dewpoints and light winds.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 215 AM EDT Saturday...We are looking at a pretty quiet period
of weather overall Sunday night into Monday with the main focus
being the above normal temperatures expected on Monday. The latest
ensemble guidance continues to suggest that the wider valleys across
the North Country will easily climb into the lower 90s with other
locations warming into the mid to upper 80s. Heat indices don`t look
all that impressive given dewpoints in the lower 60s so we likely
won`t need any heat headlines. Nevertheless, it`s always good to
take precautions when it`ll be as warm as forecasted by taking
breaks and drinking plenty of fluids. Rain chances will increase
after sunset on Monday but that will be discussed in the section
below.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 957 PM EDT Friday...Models in good agreement that a warm
and humid night will follow Monday`s hot daytime temperatures.
Low-level winds will remain out of the south Monday night in
advance of robust shortwave expected to be translating ewd
across the central Great Lakes. This should allow for overnight
lows near 70F in the Champlain and St. Lawrence Valleys, and
generally mid-upper 60s elsewhere across the North Country. It
appears that 700-500mb height falls and onset of cyclonic mid-
level flow will occur between 06-12Z Tuesday, and therefore kept
the idea of scattered to numerous showers across the region
toward daybreak.

During the daylight hours Tuesday, may see an early round of
shower activity followed by additional showers and thunderstorms
as mid-level trough and associated cold front cross the region
from W-E during Tuesday afternoon. Included a chance of
thunderstorms, with highest chances in the afternoon/early
evening time frame on Tuesday. Should see PBL dewpoints climb
to the upper 60s to lower 70s in advance of approaching cold
front, and stuck with these values shown in latest NBM. If some
breaks of sun occur between the two rounds of precipitation,
expect to see max temperatures in the mid- upper 80s. Will need
to watch for potential strong to locally severe thunderstorms on
Tuesday, as sfc-6km shear is potentially 35-40kt with moderately
strong forcing and potential for moderate SBCAPE. Will also need
to watch for locally heavy rainfall, with latest GFS indicating
high PWATs in the 1.7-1.9" range Tuesday afternoon.

Behind the cold front, temperatures will gradually settle back
closer to seasonal norms for early July with lower chances for
diurnally driven shower activity. Highs generally lower 80s in
valley locations Wednesday and Thursday, with more modest
dewpoints in the upper 50s to lower 60s expected. A northern
stream trough and secondary cold front may shift through our
region Thursday and Thursday night, allowing for cooler
Independence Day conditions with highs in the mid-upper 70s
based on current indications. Chances for showers Thursday and
Friday currently around 30 percent.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...Most sites outside of SLK will continue to
see VFR conditions through 12Z. Rain showers will track across
the international border over the next few hours with some
heavier showers briefly reducing visibilities to MVFR at EFK.
Winds will be the main terminal impact with south winds 10-15
knots and gusts to near 20 knots at all sites, with locally
higher gusts at BTV/PBG of 35 knots. Winds will continue to be
gusty through the taf period. LLWS is expected overnight at all
sites through 12Z. By 12Z, model guidance suggests ceilings will
trend towards MVFR at all sites from rain showers with some
guidance continues to suggest near or at IFR ceilings below
1000 ft agl at BTV/MPV/EFK/SLK by 18Z. Given the time of year,
confidence is low in achieving IFR ceilings, so continued trend
of ceilings only to 1000-2000 ft agl for tomorrow afternoon.
These low ceilings will be associated with periodic showers and
possibly an embedded thunderstorm tomorrow, particularly between
13-20Z. Ceilings will improve towards VFR at MSS/SLK and then
eastward beyond 22Z.

Outlook...

Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. Likely SHRA.
Tuesday: Mainly MVFR, with areas VFR possible. Chance SHRA,
Chance TSRA.
Tuesday Night: VFR. Slight chance SHRA.
Wednesday: VFR. Chance SHRA.

&&

.MARINE...
A Lake Wind Advisory is in effect for Lake Champlain today.
Winds have increased upwards of 25 to 35 knots and will
continue through the morning and early afternoon hours, with
even higher gusts possible. Waves are expected to build to 3 to
5 feet across the lake this morning. Winds across Lake
Champlain will begin to abate this afternoon but will remain in
the 15 to 25 knot range with 2-4 feet waves across the broad
lake.

&&

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

&&

$$
SYNOPSIS...Clay
NEAR TERM...Clay
SHORT TERM...Clay
LONG TERM...Banacos
AVIATION...Verasamy
MARINE...NWS BTV