172
FXUS61 KBTV 050521
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
121 AM EDT Mon Oct 5 2026
.WHAT HAS CHANGED...
As of 243 PM EDT Sunday...
No significant changes.
&&
.KEY MESSAGES...
As of 243 PM EDT Sunday...
1. An approaching cold front will keep temperatures mild
through this evening with gusty south winds. It will bring a
short period of showers Monday morning, gusty west winds, and
chillier conditions through Tuesday.
2. Potential for widespread frost and freeze conditions
primarily in eastern portions of Vermont for Wednesday morning.
As winds increase out of the south, temperatures moderate back
towards normal midweek.
3. Seasonable temperatures and periodic chances of light rain
showers are expected for the second half of the week.
&&
.DISCUSSION...
As of 243 PM EDT Sunday...
KEY MESSAGE 1: Through tonight, the system of interest which
has helped produce breezy south winds and mild weather today is
a pre-frontal trough, tied to a deepening low pressure system
over James Bay, Canada. The trough is very well defined, with a
ribbon of glaciated cloud tops and associated rain showers
tracking eastward over the easternmost Great Lake this
afternoon. These showers have produced only a trace to a
hundredth of an inch of rain upstream as precipitation falls
into a very dry layer of air. Would expect this type of rainfall
to continue as it reaches northern New York later this
afternoon before dwindling further as it pushes eastward.
A break in precipitation chances will follow tonight, then
towards midnight as the system`s cold front approaches the
International Border from the west, a vigorous piece of spin
aloft will help increase lift and force showers to blossom.
These showers will organize along the cold front oriented from
southwest to northeast, and track eastward through the morning
hours. Showers will primarily fall during the predawn hours in
northern New York, and across northern Vermont between about 6
and 9 AM. Following these showers, gusty west winds will mix to
the surface with steepening near surface lapse rates.
Widespread gusts reaching the 30 to 40 MPH range will occur
downwind of most mountain peaks across Clinton and Essex
counties in New York and central and eastern Vermont, with
otherwise 25 to 30 MPH gusts common across the region with
efficient mixing in a strong cold air advection pattern. The
strongest gusts, especially just behind the front when the top
of the mixed layer could tap into >40 knot winds near summit
layer, may result in some minor impacts as leaves fall in large
numbers. However, these winds are unlikely to produce damage or
warrant a wind advisory given the expected magnitude of winds.
Temperatures at 850 millibars, a proxy for our highest summit
temperatures, will fall below freezing by tomorrow evening as
moisture becomes very shallow. Would think some rime ice will be
possible given this set up but it cloud ice and therefore snow
is unlikely given the expected cloud temperatures and
saturation. Continued breezes tomorrow night should prevent
frost conditions and limit cooling at lower elevations, but lead
to a biting cold for this time of year; wind chills will fall
into the 20s for most locations by Tuesday morning.
Due to a reintensification of low pressure as it wraps up into
eastern Canada Monday night and stalls out, Tuesday will remain
blustery with persistent westerly breezes. While winds again
will unlikely be hazardous, there are somewhat mixed signals at
this time range as to how strong the gust potential is. The
consensus offers a slight weakening trend through the day and
peak magnitude at least 5 MPH lighter than on Monday as the low
level winds gradually weaken.
KEY MESSAGE 2: It is a tricky low temperature forecast for
Wednesday morning as guidance has trended southward and faster
with the progression of the next trough, which introduces return
flow earlier in the night. In general, it looks like from the
Champlain Valley and points west, temperatures are likely to
plummet after dark Tuesday and then stabilize or rise by
midnight or so. Meanwhile, in much of Vermont the surface should
decouple from the milder air aloft, and this should persist
such that low temperatures continue falling through the night
and drop back to near or below freezing. As such, while
widespread frost/freeze is indicated, would not expect any
Frost/Freeze products as the growing season from our perspective
only remains in the Champlain Valley where it is looking less
likely to see frost conditions develop.
Breezy south winds will probably necessitate another Lake Wind
Advisory with trends towards a deeper low passing closer to our
region on Wednesday, not too dissimilar to today with a warm
front pushing through our region with plentiful dry air. Only
small chances of rain, and mainly towards the evening and
primarily in western portions of northern New York, are being
offered. These probabilities increase after sunset, although
have noted the ECMWF and its ensembles have about a six hour
earlier arrival of showers than the GEFS; timing of showers are
fairly uncertain. Most likely high temperatures are in the upper
50s to low 60s, or roughly 10 degrees higher than the early
week highs.
KEY MESSAGE 3: Heading into the latter half of the week, high
pressure will shift eastward, with southerly flow allowing for
more seasonable temperatures. Daytime high temperatures will
climb into the upper 50s to mid 60s, with overnight lows in the
30s to mid 40s. Throughout the week, several north stream
systems will skirt across the region, allowing for some periods
of light rain showers, although nothing looks significant at
this time. The best chances for some light rain showers will be
further north towards the border, with drier conditions further
south. Although there will be several chances for showers, drier
conditions look to return towards the weekend as ridging builds
back into the region, although trends will need to be monitored
as we get closer.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...A sharp cold front is moving east across the
northern New York, producing some visibility reductions, down to 2SM
at KMSS at 04z, within convectively enhanced showers. As the feature
approaches Vermont, it is expected to slowly decay, and then exit
east around 12-13z. A west wind shift will take place behind it,
along with a gradually increasing period of winds and some patchy
MVFR ceilings. Brisk west-northwest flow will result in 12-17 knots
surface winds with gusts 20-27 knots, mainly 15z-23z. Some scattered
showers are expected to redevelop during the afternoon behind the
feature, and there are PROB30s noted for that potential. Winds
decrease overnight, but likely remaining around 5-10 knots out of
the west to northwest.
Outlook...
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Patchy frost.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. Slight chance SHRA.
Thursday: VFR. Chance SHRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: Mainly VFR, with local MVFR possible. Chance SHRA.
&&
.MARINE...
Southerly channeled flow this morning has already resulted in
observed sustained winds at Colchester Reef up to 25 knots, and
low level flow will remain strong through tonight before finally
relaxing around daybreak Monday. This extended period of
southerly flow ahead of a cold front will result in a seiche
effect on the broad lake, as well. Wave heights in the 2 to 4
foot range are likely during this period on the broad and
northern waters, peaking overnight.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Kutikoff
DISCUSSION...Kremer/Kutikoff
AVIATION...Haynes
MARINE...Kutikoff
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