019
FXUS61 KBTV 092327
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
727 PM EDT Wed Sep 9 2026
.WHAT HAS CHANGED...
As of 256 PM EDT Wednesday...
The axis of the highest rainfall amounts through Thursday early
morning has slightly shifted south into Central Vermont.
Though, there still are no hydrological concerns expected.
&&
.KEY MESSAGES...
As of 256 PM EDT Wednesday...
1. Widespread rain is expected to continue through tonight with
gusty winds from the south and southwest.
2. A drier, fall-like, period is anticipated to end the week as
gusty winds persist Thursday, decreasing toward the weekend.
3. A pair of similar cold fronts will likely pass through the
region Sunday night and Tuesday night. Breezy periods and some
showers are expected with no significant hazards anticipated.
&&
.DISCUSSION...
As of 256 PM EDT Wednesday...
KEY MESSAGE 1: Our weather system has arrived in portions of
northern New York at the time of this discussion, with radar
denoting areas of stratiform rain showers across the Adirondacks
and St. Lawrence Valley. Isentropic lift along a warm front
will continue to spread east this afternoon with light to
moderate stratiform rain moving into central and northern
Vermont. Stratiform rain will become more broken and scattery by
this evening as a strong low level jet of 40- 50kts at 850mb
builds in. While most of these stronger winds aloft will not be
realized due to concurrent precipitation, gusts between 25-35
MPH will be possible, especially in the favored south-north
channeled valleys. For mariners, a Lake Wind Advisory is in
effect for Lake Champlain through at least tomorrow morning. The
low-level jet will be associated with a small warm sector ahead
of a clearing cold front which will help transition showers
around sunset to more convective driven showers. Instability
will be elevated and not surface based, and likely will be
competing with the preceding stable air from todays stratiform
rain. That said, a few isolated rumbles of thunder, primarily in
the St. Lawrence Valley and Adirondacks will be possible with
just under 500J/kg of elevated MLCAPE analyzed currently, and
subsequent strong 40-50knots of shear. No severe or strong
storms are expected, however.
While the system will be fairly progressive, Pwats in the
latest CAMs denote elevated values to around 1.8-2.25 inches
areawide with warm cloud depths to 12,000ft agl. As rain turns
more showery towards later this afternoon and evening, heavy
downpours will be possible. Rain should be beneficial with the
recent dry stretch and antecedent dry conditions through this
summer, thus no hydrological concerns are anticipated with this
system. Precipitation amounts will be highest across the St.
Lawrence Valley, higher terrain of the Adirondacks and spine of
the Greens, and near the International Border. Recent CAMs have
begun to trend some higher rainfall amounts a bit south into
central Vermont. While these are likely contaminated with more
robust convection that appears unlikely, this trend south has
been reflected in the latest QPF forecast, where rainfall
amounts along a line from Tupper Lake, NY to eastern Addison
have been slightly increased. Some shadowing and less robust
convection will help to reduce the magnitude models are
suggesting. Blocked flow with low Froude numbers will also
likely lead to some orographic enhancement of precipitation
totals along the spine of the Greens. Around three-quarters of
an inch to and inch of rain will be possible in the
aforementioned locations, with a quarter to half an inch most
other locations; lower amounts likely in southeastern Vermont,
and in portions of the central Champlain Valley due to shadowing
from the Adirondacks. Temperatures tonight will be mild in the
mid 60s with precipitation and humid conditions ongoing. Rain
showers will taper off towards sunrise Thursday morning, with
slightly weakening winds.
KEY MESSAGE 2: Our dynamic weather system today will slide east
Thursday morning with drier low level conditions mixing in from
the north and west. Mid level moisture will linger into
Thursday afternoon with some clearing conditions, mainly in the
wider valley; the higher terrain will likely remain partly to
mostly cloudy tomorrow. Temperatures will be warmer than today
with mixing and highs in the mid to upper 70s. Winds will become
gusty once again Thursday afternoon with good vertical mixing
associated with a lagging low level jet, and drying low levels
behind the Wednesday system. Winds will gust between 20-30 MPH,
primarily in the channeled north to south valleys of the Vermont
and New York. Winds will trend weaker by late Thursday with
calmer northwest cold advection by Friday. Depending on how fast
winds slacken Thursday evening, and how fast drier low levels
will advect, some patchy fog, mainly in the Adirondacks, and
perhaps the St. Lawrence Valley, will be possible, as skies will
begin to clear overnight from west to east. Vermont will likely
lag behind in the clearing department with clouds lingering
towards sunrise Friday. Thursday night lows will dip into the
40s for most of the region, outside of areas near Lake
Champlain. The Adirondacks have the best opportunity to radiate
out with some pocket upper 30s in the typical coldest hollows.
A picture perfect weekend looks to be in store, beginning
Friday through Saturday. Temperatures will trend slightly below
seasonable levels Friday as northwest flow advects cooler air
from Canada. Highs will be in the mid 60s to near 70 with clear
skies. A few light breezes near the International Border, and
Champlain Valley, to 10-15 MPH could bring a slight bite to the
air Friday afternoon. Clear skies will persist Friday night with
areawide strong radiational cooling. Temperatures will cool
into the low to mid 40s for most locations, and near 50s for
areas around Lake Champlain. Raw guidance is hinting at
potentially low to mid 30s for areas in the heart of the
Adirondacks and within the climatologically favored sheltered
valleys of the NEK and Adirondacks. Friday night, as opposed to
Thursday night, looks like the better night for patchy valley
fog in the favored river valleys of Vermont and northern New
York. Saturday looks to be a repeat of Friday with slightly
warmer highs into the mid to upper 40s with mostly clear skies.
Some breezy channeled winds in the Champlain Valley will be
possible Saturday afternoon with winds turning more southerly,
hence our warmer temperature advection. Other than some breezy
conditions, Saturday looks to be another gorgeous day.
KEY MESSAGE 3: An active pattern from Sunday through Tuesday
will be present across the US with a storm track persistently
well to our northwest, as low pressure systems move from near
Lake Superior into the vicinity of Hudson Bay. Fast moving,
mainly westerly mid and upper level flow will help push frontal
boundaries through with modest pooling of moisture as strong low
level advection and convergence occurs. So rounds of scattered
to numerous showers both on Sunday and Tuesday, especially in
the afternoon to evening hours, are expected.
For Sunday, it appears a shortwave passing to our south may
bring some light rain to our southern areas earlier in the day
ahead of the primary event; PoPs have increased as high as
20-29% in southern portions of Vermont by daybreak. Otherwise,
no real changes are noted in the rainfall forecast with most of
the moderate rainfall chances closer to the International
Border. The Tuesday system looks more dynamic with stronger wind
fields, including high probabilities of 40 MPH gusts in the
vicinity of Lake Champlain out ahead of its cold front. Heavier
rainfall potential likewise is elevated for this event, with 1"
in 24 hours ending daybreak Wednesday in the 10-20% range fro
much of northern New York and much of northern Vermont.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...Widespread light to moderate rain is
leading to MVFR conditions across most terminals at this time.
Conditions may occasionally lower to IFR in any heavier rain.
Temporary IFR conditions may happen through 06z, and before
winds turn westerly in the 08Z to 12Z period with the approach
and passage of a cold front towards early morning which will
lead to improvement to VFR conditions as cloud bases scatter and
lift.
Aside from at BTV and RUT where sustained winds are 12-15 knots
with higher gusts, winds are relatively light at the surface.
With increasing winds aloft after 00Z, most sites should expect
significant LLWS with southwesterly winds at 2000 feet agl
reaching as high as the 40-50 knot range at times outside of the
Champlain Valley. These conditions will occur mainly 00Z-06Z in
northern New York and 02Z-08Z in Vermont, concurrent with
showers that may briefly be heavy at all terminals. Westerly
winds will become gusty in the 20 to 25 knot range from 14Z-18Z.
Outlook...
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. Patchy BR.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: Mainly MVFR, with local IFR possible. Chance SHRA.
Sunday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Monday: VFR. NO SIG WX.
&&
.MARINE...
Southerly wind gusts 15 to 30 knots are expected on Lake
Champlain through this evening, weakening back to 10 to 20 knots
after midnight tonight. Waves will be around 1 to 3 feet on the
southern and northern waters, and 2 to 4 feet on the broad
waters through midnight. Wave heights will lower to 1 to 3 feet
for the entire Lake after midnight tonight. Winds will become
weaker tomorrow morning to 10 to 15 knots, increasing to 15 to
20 knots by tomorrow afternoon.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Danzig
DISCUSSION...Danzig/Kutikoff
AVIATION...Neiles
MARINE...Storm
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