FXUS61 KBTV 250228
Area Forecast Discussion
National Weather Service Burlington VT
1028 PM EDT Sun Sep 24 2023
We remain on the northern fringes of a post-tropical storm.
Meanwhile, the approach of a weak surface cold front bringing
high altitude wildfire smoke from the north will help hold the
storm to our south. Aside from isolated afternoon showers
tomorrow, high pressure will effectively build in through the
upcoming week. As a result, seasonable and dry weather will
prevail through the end of the week and possibly beyond.
.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 1011 PM EDT Sunday...Main tweak was to the hourly
temperatures. The rate of cooling has been variable, but
the infamous cold hollow that is the Adirondack Airport near
Saranac Lake has reached 41 already. Based on the afternoon
dewpoints, it seems reasonable to assume they could get a few
degrees colder and have noted similar trends near Ellenburg, NY
and Island Pond, VT. Also noting a few areas starting to report
visibilities in the realm of 5 to 9 miles in northern Vermont
and northern New York, suggesting some fog could be trying to
form. Most locations still have awhile before they reach their
crossover temperatures, and there is expected to be a boundary
shifting south. Nevertheless, fog has been expanded in the
forecast. All else is in fairly good shape. Have a great night!
While no impactful weather is expected through tomorrow night
as temperatures remain seasonable and little to no rain falls,
there is quite a bit of interesting meteorology going on across
our region. The main items of interest are wildfire smoke and
patchy fog. There also is a chance of light showers tomorrow
afternoon associated with lingering low level moisture and
steepening low level lapse rates, mainly in the southern half of
Vermont and adjacent Essex County, New York.
Two distinct ribbons of smoke are currently evident in both
satellite and webcam images and generally consistent with
modeling. The first one is currently over northern New York and
Vermont, which is mixing with high clouds still streaming
northward from post-tropical storm Ophelia. Air quality remains
moderate and not expected to degrade. Then more smoke is present
well to our north over central Quebec province and southeastern
Canada, on the cool side of a surface cold front helping spark
cloud streets in southern Quebec. This smoke will continue
moving southward behind the front and become situated over much
of our region tomorrow, likely producing a milky sky with
otherwise sunny conditions. As surface low pressure to our south
drifts eastward, our large-scale wind direction will remain
more easterly than northerly, which will support relatively
light winds in north/south valleys during the day while the St.
Lawrence Valley sees breezy conditions with gusts upwards of 25
MPH. This easterly flow will help the smoke drift westward
through the day and largely exiting our area overnight. As has
been the case in recent days and weeks, smoke is not expected to
cause respiratory issues with low concentrations near the
surface based on both upstream observations and modeling.
As for valley fog, we remain in peak climatological fog season
and with shortening days, any fog that develops tends to stick
around longer. At the same time, there is a lot of dry low level
air, which has mixed down in pockets with sharply lowering dew
points this afternoon. The southward push of strong Canadian
high pressure will help generate some increasing winds
aloft/higher terrain, as well, which will reduce radiation fog
potential even as skies largely clear. That being said, while
fog is not explicitly forecast at this time for the overnight
hours, it would not be surprising to see patchy dense fog in
sheltered locations, especially in central and eastern Vermont.
Tomorrow night may more of a traditional cool, clear night as
the surface high better asserts itself in our region, with more
typical fog development especially in northern New York.
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
As of 250 PM EDT Sunday...Picture perfect fall weather will persist
through much of the week as high pressure settles directly overhead.
Abundant sunshine and near normal temperatures can be expected each
day. Nights will be on the chilly side as we`ll have optimal
radiational cooling; patchy fog will also be possible in the favored
valley locations. Patchy frost may also be possible in the cold
hollows of the Adirondacks and Northeast Kingdom, so subsequent
shifts will need to monitor for the need of any headlines.
.LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 250 PM EDT Sunday...The ridge starts to break down as we head
into the weekend, though model guidance differs on details. The GFS
is the most robust in keeping the high overhead, while the CMC and
ECMWF indicate the ridge axis shifting eastward while an upper
trough swings into the Great Lakes. Both of the latter models
develop a surface low off the Mid Atlantic coast over the weekend as
the upper trough moves eastward, but still keep the high entrenched
over northern/eastern New England. All in all, the weekend still
looks dry as best chances for any showers will remain well to our
south. At worst, current expectations are we`d see increased cloud
cover, which would help keep overnight temperatures closer to
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Through 00Z Tuesday...Mid to high clouds continue across the
Adirondacks and south-central Vermont. Some visibility
reductions are being noted at KMPV and KMSS, perhaps from some
near surface smoke. Observations indicate this should shift
south and away without further reductions. Winds will trend
light and terrain driven through about 10z before north to east
winds increase. Seasonal fog should develop in Vermont valleys
between 06z and 12z. KMSS and KSLK have a lower potential for
fog due to drier air and early arrival of northeast winds, but
did note potential with a tempo for 3SM visibility around
sunrise. Beyond 13z, wind speeds pick up to 8 to 14 knots
sustained with gusts 15 to 20 knots possible, particularly at
KMSS. Fair weather cumulus with bases 5000-7000 ft agl are
likely between 15z and 21z. After 22z, winds will begin to
subside, but remain around 4 to 8 knots.
Monday Night: VFR. Patchy BR.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Patchy BR.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.