Swanton, Vermont 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

964
FXUS61 KBTV 171755
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
155 PM EDT Thu Apr 17 2025

.SYNOPSIS...
Conditions will be much drier today with low humidities and
breezy winds. While widespread fire weather concerns are low due
to recent wet conditions, some very isolated locations in the
eastern Adirondacks may be susceptible to fire spread this
afternoon. The next system will bring more wet conditions with
widespread rain over the weekend with unsettled conditions
continuing into early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 155 PM EDT Thursday...Clouds have completely cleared the
region, leading to bountiful sunshine areawide. The April sun
has trended temperatures near the 90th percentile this morning
with dew points falling near the 10th percentile. Updates were
to trending dew points down and temperatures up, leading to RHs
between 20-30%. Surface winds have also been locally higher,
especially in the valleys where dry air entrainment has led to
enhanced mixing of stronger winds aloft. Increased wind gusts
slightly across the Champlain Valley to reflect this. Dry and
mild conditions will continue through this evening.

Previous Discussion...Very dry conditions are expected today
with ample mixing bringing 20-30 mph wind gusts and RH in the
20-35% range for valley locations today. Most locations do not
have much in the way of fire weather concerns given recent wet
conditions. The exception will be some very isolated spots to
the lee of the Adirondacks in eastern Essex Co, NY. There could
be a brief window of gusts in excess of 25 mph and RH below 30%
this afternoon. While not overly concerning, care should be
exercised to not create a spark. Otherwise, winds decrease
sharply tonight with strong radiational cooling expected and
decoupling of surface winds from winds aloft. Most locations
will see temperatures drop to around/slightly below freezing
with colder hollows of the Adirondacks and northeastern Vermont
cooling to around/slightly below 20 degrees. Models were
overwhelmingly moist today and warm overnight, so 10th
percentile guidance was used to balance what was being presented
in model soundings and what average guidance favored. High
temperatures will warm from the 40s to low 50s today to the 50s
and low 60s Friday. Precipitation chances increase Friday
afternoon heading into the evening as a frontal system tracks
towards the region. CAMs continue trending this boundary
becoming quasi-stationary north of the Canadian border, so
trends have pushed best chances of precip more northward from
the previous forecast.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
As of 343 AM EDT Thursday...Elevated thunderstorms - loud thunder
with a light show, but without particularly heavy rain or hazardous
wind or hail - remain possible with showers Friday night, especially
the first half of the night. An elevated mixed layer will move over
the area, and as the bottom of this layer warms/moistens any showers
could easily be capable of producing lightning. Greatest
probabilities generally are in northern and western portions of our
area (limited chances of thunder over southern/eastern Vermont),
related to the expected trajectory of the anomalous moisture and its
gradient as a frontal system moves to the northeast. With rounds of
showers moving parallel to the boundary with a strong low level jet,
a narrow zone of heavy rainfall (roughly 10% chance of greater than
1") is possible in the early morning hours, especially areas near
the International Border in northern New York.

This frontal system will be mainly to our north and west Saturday
morning, and the pre-frontal environment will become moderately dry
and warm with only some widely scattered showers during the day. Low
level conditions will be seasonably warm and moist with breezy
conditions, favorable for significant high elevation snow melt. The
low level wind fields don`t look particularly strong as the pressure
gradient will be modest. Typically breezy channeled southwesterly
flow in the St. Lawrence Valley will locally increase winds in this
area. Meanwhile, warm air over top cold lake water will limit
southerly winds in the vicinity of Lake Champlain. 925 millibar
temperatures near 15 degrees Celsius across much of Vermont and dry
adiabatic mixing will yield widespread highs in the 70s. Note that
850 millibar temperatures are progged to be near 10 degrees Celsius,
such that with more sunshine, mid to upper 70s in our lower
elevations could occur in the "best" case scenario. As the weak cold
front moves eastward associated with low pressure moving into
northern Maine towards evening, showers may organize a bit but with
a capping inversion and dry air aloft, coverage and intensity of
showers should remain unimpressive. So while there are chances of
rain throughout the day, think most of Saturday will turn out dry
with skies trending at least partially sunny outside of these
showers.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
As of 343 AM EDT Thursday...A few lingering showers, mainly in higher
terrain, will persist Saturday night and possibly end as some wet
snow as the freezing level drops dramatically behind the cold front.
More notable will be breezy west-northwest winds. A glancing blow of
polar air will come across the region, helping to produce deep
mixing, especially after sunrise. Thankfully wind speeds at the top
of the layer look modest enough to support sub-advisory level winds,
consistent with climatologically typical wind speeds at 700 and 850
millibars per NAEFS guidance.

A relatively strong high pressure area will build eastward into
northern New York and Vermont Sunday night, which suggests good
radiational cooling and potentially lower temperatures than
currently forecast. Sub-freezing temperatures will be common Monday
morning, typically cold for late April. With dry air and sunshine,
temperatures should warm nicely into the 50s Monday ahead of the
next frontal system passing to our north and west Monday night.
This frontal system looks less dynamic than the one late this week,
with lesser temperature swings and little risk for thunder/heavy
rain. Greatest chances of widespread showers continues to be during
the first half of Monday night. Precipitation chances Tuesday could
drop more than currently indicated assuming the primarily low passes
well to our north. Greater probabilities of any substantial rain
Tuesday into Tuesday night is over northeastern Vermont, closer to a
potential secondary low and associated upper level low. The latest
GFS seems to be an outlier with regards to the push of much cooler
air and wetter conditions in our region; will need to monitor trends
as there is generally significant spread for Tuesday in temperatures
and precipitation. Conditions for Wednesday generally look dry and
seasonably mild ahead of yet another frontal system.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Through 18Z Friday...Clouds have all but dissipated and moved
out leaving clear skies at all terminals. This trend will
continue through the TAF period. This clearing has led to breezy
northwest winds between 10-15 knots with gusts up to 25 knots
across the area, especially in valley terminals. Winds aloft are
causing light to moderate turbulence, especially at mountain top
elevations. Terrain confined winds are expected after 23Z with
surface winds becoming variable and calm through the remainder
of the TAF period.

Outlook...

Friday Night: VFR. Chance SHRA, Slight chance TSRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. Chance SHRA.
Monday Night: Mainly VFR, with local MVFR possible. Likely SHRA.
Tuesday: Mainly MVFR, with local IFR possible. Chance SHRA.

&&

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

&&

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