-- Discussion containing changed information from previous version are highlighted. --
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FXUS61 KBTV 251003
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
603 AM EDT Wed Sep 25 2024

.SYNOPSIS...
Early morning showers will wind down toward this afternoon, but then
more widespread precipitation will spread over the region tonight
and Thursday. Total rainfall amounts of 1 to 2 inches are expected.
Drier weather returns for the weekend, along with seasonable
temperatures.

&&

.NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --
As of 600 AM EDT Wednesday...Showers continue their eastward
trek across the region this morning. The bulk of the activity
now lies across the Champlain Valley and into the northern
Greens, and extends a bit further south and east than previously
anticipated. The rain has been moderate at times, and while most
locations have received less than a quarter of an inch, portions
of the Adirondacks are reporting totals of half an inch or more.
Have made adjustments to PoPs to match the radar trends, and
adjusted QPF for the past 6 hours to incorporate the latest
reports. Otherwise the forecast remains in good shape and no
other changes were needed with this update.

Previous discussion...Overall scope of the forecast remains
unchanged, with some much welcome rainfall to occur across the
region through the period. We have increased the total rainfall
forecast a decent amount with this package, as we`re now that
we`re within the realm of hi-res guidance. Noted that ensemble
guidance is indicating at least an 85% probability of exceeding
1 inch in most locations over the next 36- 48 hours. However,
flooding is still not a concern, especially given how dry we`ve
been recently.

Our first round of showers is pushing east-northeast across mainly
northern/central portions of the forecast area early this morning,
with precipitation amounts generally a quarter of an inch or less so
far. This scattered shower activity will exit to our northeast by
mid morning, and expect we`ll see a brief dry period for a few hours
thereafter. Skies will remain cloudy though, and temperatures will
be on the cool side as a result. Highs will range from the upper 50s
to mid 60s this afternoon. The break in the precipitation will also
allow for some mixing, and expect winds will be a little on the
breezy side as a result. Gusts around 25 mph will be possible,
especially on the northern slopes of the Adirondacks and in the
Champlain Valley.

After this afternoon`s brief stint of mostly shower-free conditions,
expect precipitation to redevelop later this evening and overnight.
The upper trough currently crossing into central Ontario will dig
into the eastern Great Lakes overnight, closing off into low
pressure which will then scoot along the international border on
Thursday. Favorable lift and jet dynamics and increasing moisture
will allow widespread showers to move northeastward into our area
starting this evening but especially overnight. Meanwhile, the upper
trough will pivot eastward across Ontario, dragging a frontal
boundary along in its wake. This feature will serve as a focus for
moisture convergence as it moves eastward across our area Thursday.
With PWATs approaching/exceeding 1.5 inches and warm cloud depths of
10-12 kft, briefly heavy rainfall will be possible, and several of
the latest hi-res CAMs are indicating a broken line of more robust
showers along/ahead of the frontal boundary. Drier air quickly moves
in after the frontal passage, bringing widespread precipitation to
an end. Scattered showers may redevelop behind the front though as
the core of the upper low moves by just to our north. The cold pool
associated with the low will steepen lapse rates and allow for a bit
of instability, so there may be a few rumbles of thunder along the
international border. All in all, expect 1 to 2 inches of rain to
fall across the region, with locally higher amounts possible in
areas that perhaps see repeated rounds of heavier showers. While
some ponding in poor drainage areas may be possible in heavier
rainfall rates, the antecedent dry weather and low river flows keep
the threat of any flooding low to none.

Otherwise, we could still see some breezy conditions overnight
tonight, though widespread rainfall will limit mixing potential. At
the least though, winds will remain gusty over Lake Champlain, and a
Lake Wind Advisory will likely be needed later today and overnight
tonight. Winds will abate during the day on Thursday, turning more
toward the west/southwest once the front moves through. Ample
moisture and cloud cover will keep lows in the 50s areawide tonight.
Tomorrow should be warmer than today from the Champlain Valley
westward where some sun may make an appearance behind the front, but
eastern VT will likely see another day with highs in the upper
50s/low 60s.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
As of 341 AM EDT Wednesday...The cold front should have passed to the
southeast by the start of this period, but some associated rain is
possible for a few hours in southern and eastern areas Thursday
night. Lingering moisture in the low-levels and northwest flow could
cause a few isolated showers across the higher elevations of
northern Vermont during the day on Friday. They would be most likely
to occur in the afternoon when there is also the influence of
diurnal heating. However, any shower would be brief and relatively
unimpactful. Low clouds look to hold stubborn in many areas in a
more winter-type pattern, though there should be some breaks of sun
as well. Highs will be in the mid-60s to low 70s, slightly above
climatological normals despite the cloud cover and northwest flow.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 341 AM EDT Wednesday...Surface high pressure builds into the
region for the weekend and into the start of next week. The airmass
will originate from the central/western US so any of the coldest air
will remain well to the north over Canada. Temperatures will
continue to be a bit above climatological normals, with highs
generally in the upper 60s to mid 70s, and lows generally in the
upper 40s to mid 50s. Fog formation is possible in the
climatological favored valleys overnight as there should be light
boundary layer winds. The one area of uncertainty for fog is cloud
cover. The low-level moisture from Friday looks to linger into
Saturday and may inhibit fog formation in the areas that remain
cloudy. Also, some high clouds look to try to build into the region
from the remnants of Helene. However, these currently look to
struggle to make it, and anything that does would be very high and
thin, and therefore not likely to have a significant impact on
radiational cooling. The next chance of rain is in the middle of
next week as a cold front passes through. The front will try to
bring some of the moisture from the remnants of Helene north and
into the region, but even if it does, the rainfall still should be
relatively light and not enough produce a flood threat. Less than 20
percent of EC/GFS/Canadian ensemble members have more than 1 inch in
24 hours and none have more than 2 inches.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
Through 06Z Thursday...VFR conditions will prevail at all
terminals for the first half of the forecast period, with
conditions gradually deteriorating to MVFR thereafter. Showers
already overspreading the region at this hour, but visibility is
generally remaining unrestricted and ceilings AOA 3500 ft. First
round of showers will push eastward over mainly northern/central
portions of the region through 15z, then expect a brief break in
precipitation. Ceilings gradually lowering to 3500-4500 ft
through the daylight hours. More widespread precipitation moves
in from southwest to northeast after 22z Wed and continues
through the remainder of the TAF period; expect MVFR ceilings
and visibilities to prevail as this rain affects the terminals.
Winds will generally south/southeast between 6-12 kt throughout
the TAF period, with some gusts around of 15 to 20 kt possible,
mainly after 14z Wed. LLWS expected through 12z at KMSS early in
the period, and then again at all northern NY terminals toward
04z onward as a low level jet moves through the region.

Outlook...

Thursday: MVFR/IFR conditions possible. Chance SHRA.
Thursday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.
Friday: Mainly VFR, with local IFR possible. NO SIG WX.
Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Sunday: VFR. NO SIG WX.

&&

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

&&

$$
SYNOPSIS...Hastings
NEAR TERM...Hastings
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Hastings