FXUS61 KBTV 220242
Area Forecast Discussion
National Weather Service Burlington VT
1042 PM EDT Thu Sep 21 2023
High pressure remains firmly over the North Country bringing ample
sunshine with areas of fog in river valleys and colder hollows
overnight; some frost cannot be ruled out for in the Adirondacks.
Low pressure off the mid Atlantic tracks towards the Northeast for
the weekend bringing periods of rain with more isolated showers
potentially lingering through Monday into early next week.
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 1042 PM EDT Thursday...Forecast remains in good shape
with localized patchy fog evident in northern New York and
Vermont at this hour, which should become more widespread as the
night wears on. Dew points are generally running a bit higher
than expected, which may suggest our low temperatures might be
slightly too cool. With our strong radiational cooling
conditions, dew points and temperatures should fall off
overnight enough to not make any changes to the previous
* Potential for localized frost/freezing fog in the Adirondacks
late tonight into early Friday morning.
High pressure will remain firmly in control of expected conditions
for the North Country through Friday. With the ridge axis overhead,
subsidence will be strong supporting night-time fog formation with
clear skies and light winds. Being another day removed from
precipitation, fog chances will be highest in river valleys and
colder hollows. With near surface soil moisture evaporating or
percolating, dew points below 2 meters should be able to fall
sufficiently cool to warrant some frost potential in the
Adirondacks, mainly in the vicinity of Saranac Lake. With
temperatures falling to around freezing, its feasible to have a
brief period of freezing fog as well in the typically colder
hollows. Elsewhere, temperatures will remain well above freezing
with no appreciable chances of frost. Otherwise, ridging crests
Friday with another day of ample sunshine. Continued drying will
promote conditions favorable for temperatures to warm above seasonal
averages in the upper 60s to mid 70s. As ridging breaks down Friday
night, cloud cover will begin to increase south to north limiting
radiational cooling and fog potential allowing temperatures to
linger in the 40s to low 50s for most locations.
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 318 PM EDT Thursday...All eyes have turned to potential
tropical cyclone 16 which is currently located over the western
Atlantic north of the Bahamas. There has been increasing model
confidence that this system, which is currently extratropical (cold
core) will develop tropical characteristics in another 24 to 36
hours. Whether it develops tropical characteristics or not, the
potential impacts, or lack thereof, will be the same. This system is
expected to hug the coastline as it approaches the Mid-Atlantic
coastline on Saturday with increasing chances for rainfall across
southern Vermont late in the day on Saturday into Saturday night.
There is still a lot of disparity amongst the deterministic guidance
how far north the precipitation shield will spread given
interactions between the potential cyclone and a frontal boundary.
Instead of going a deterministic approach with this forecast cycle,
we have leaned heavily on probabilistic and ensemble models which
shows a quarter of an inch or less across far southern Vermont with
a sharp gradient to no rainfall expected from central Vermont
northward and for much of northern New York. Still, with this
potential tropical cyclone in the early stages of development, a lot
of uncertainty exists until the RAOB network is able to sample how
the environment is reacting to this system. Stay tuned for more
updates but impacts at this time appear minimal at most.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 318 PM EDT Thursday...A sharp northern stream shortwave is
expected to help drive a cold front through the region on Sunday
which is expected to push out any lingering precipitation associated
with the potential tropical cyclone. Some models show the remnants
of the upper low attached the potential tropical cyclone phasing
with the longwave pattern on Sunday which could enhance
precipitation along the frontal boundary should this occur. However,
as mentioned before, confidence in any one solution remains low
until we have more time to sample this system. Following the frontal
boundary, Canadian high pressure is expected to settle into the
North Country which is expected to bring seasonable temperatures,
plenty of sunshine, and minimal chances of rainfall through much of
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...VFR conditions under high pressure will
prevail during daylight hours. Fog is expected to reform
overnight as surface radiates out heat. The usual suspects of
SLK/MPV should have no problem fogging in with LIFR conditions
despite being displaced another day from rainfall; SLK could see
some brief freezing fog between 09-12Z. Expect at least
temporary BR with mix of MVFR and IFR conditions at EFK/MSS/RUT.
BTV/PBG should stay out of fog, but expect river fog along the
Winooski to be present just north/northeast of the BTV terminal.
Another day of VFR will occur with fog/stratus lifting and
scattering by 14Z, with just some fair weather cumulus
preferred over higher terrain mainly between 15Z and 20Z.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Slight chance SHRA.
Sunday: VFR. Slight chance SHRA.
Sunday Night: VFR. Slight chance SHRA.
Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
Monday Night: Mainly VFR, with areas MVFR possible. Slight chance
Tuesday: Mainly VFR, with areas MVFR possible. NO SIG WX.