859
FXUS61 KBTV 202300
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
700 PM EDT Mon Oct 20 2025
.SYNOPSIS...
Areas of rain showers will continue to impact the region tonight
with localized heavy downpours possible. A period of gusty westerly
downslope winds are expected over the eastern Adirondacks this
evening. Rain showers will taper off on Tuesday, before additional
showers redevelop by Tuesday night into Wednesday. A cooler and
unsettled weather pattern will prevail for most of the week
ahead.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 654 PM EDT Monday...The low`s center is tracking across
Essex County, NY and Addison/Rutland Counties of Vermont
allowing for increased forcing for ascent and resulting in some
thunderstorms. The forecast was updated through 10 PM to keep
thunderstorm chances ongoing until nocturnal stabilization
offsets forcing. The chances were extended northward into
southern Chittenden County and western Windsor County as well.
Previous Discussion...Rainfall amounts have varied greatly
today acrs our cwa from amounts near 0.10" to localized values
over 1.20" near the Western Slopes. Crnt radar shows bands of
light to moderate rain continue to pivot from southeast to
northwest acrs our cwa, as deep negatively tilted trof conts to
evolve. RAP13 analysis places closed 7h/5h circulation near KALB
with deep moist conveyor belt of sub- tropical moisture
advecting into our cwa. As system conts to mature over the next
1 to 3 hours, expect a backside deformation/commahead of precip
to develop over central NY and slowly move into our cwa
overnight. Guidance still indicates pockets of CAPE btwn 250-400
J/kg thru this evening, which could result in a few embedded
rumbles of thunder. This idea is confirmed by latest lightning
data showing a few strikes on back edge of deeper moisture ahead
of potent s/w energy. Any convective elements wl be capable of
localized heavy downpours, given pws btwn 1.0 and 1.25". As
backside deformation develops with north/northwest upslope flow
expect areal coverage of precip to redevelop overnight,
especially northern Dacks/CPV and north-central mtns of VT.
Additional qpf wl be 0.25 to 0.75" overnight with localized
amounts of 0.75" to 1.25" likely in favorable trrn focused
areas. Feel NBM is way too quick in lifting precip/moisture out
of our cwa on Tues morning, given closed cyclonic system, so I
have carried likely/cat pops thru 12z and slowly taper off by
18z Tues. Additional qpf can be expected thru 15z along the
western slopes/northern dacks and eastern CPV on Tues morning.
Lows mainly in the 40s tonight warm back into the 50s to lower
60s on Tues. Also, a period of gusty westerly winds of 30 to 45
mph are likely this evening acrs the eastern downslope areas of
the dacks, associated with 925mb winds of 35 to 45 knots.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 250 PM EDT Monday...Guidance in good agreement with next closed
mid/upper lvl cyclonic circulation developing over the central Great
Lakes with multiple embedded s/w`s and boundaries impacts our cwa
thru Weds night. This wl result in an unsettled wx pattern for
midweek with multiple rounds of showers likely, but qpf wl be
lighter given pws dropping into the 0.50 to 0.75". In addition,
qpf/pops wl become more trrn focused for midweek given wind speed
and direction and position of closed system. Initially our cwa wl be
on the warmer side of the low, but eventually progged 850mb temps
drop below 0C, supporting some potential for very high summit snow
by 12z Thurs. The freezing levels are near 4000 ft, so no impacts
and just a very minor slushy accumulation possible. Progged 850mb
temps hovering either side of 0C is not great for individuals
looking for snow accumulations in mid/late Oct. Otherwise, temps are
mostly in the mid 50s to lower 60s on Weds and cool into the mid 30s
to mid 40s on Weds night.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 250 PM EDT Monday...A large scale gyre will continue to
cyclonically rotate just south of James Bay in Canada with multiple
shortwaves and chances for precipitation in the extended. Cyclonic
flow will usher in mainly cloudy skies through the remainder of the
week with relatively seasonable temperatures. Highs will be in the
upper 40s to low 50s with overnight lows upper 20s to 30s.
System wise, cyclonic flow will lead to southwesterly flow Thursday
which means we will be talking lake effect showers and clouds. Lake
Ontario temperatures are about 15C with 925mb temperatures around 3-
4C. This temperature difference with the southwest flow along the
lake fetch will be favorable for lake effect showers and clouds that
should make it into portions of southern St. Lawrence County and
southern Franklin County in New York. The lake effect machine will
remain on through at least Saturday with prevailing southwesterly
flow. Weak shortwaves both Friday afternoon and Saturday afternoon
will bring shower chances to the region, with better chances in
higher terrain of the Adirondacks and northern Greens. 925mb
temperatures will be around freezing so wet snow atop the mountain
summits remains likely through the end of the week. While we will
see round of precipitation chances, the actual amounts will be both
spotty and low due to somewhat drier air left behind by the
Wednesday system. The upper level gyre will gradually depart to the
northeast this weekend with some lingering shortwaves trailing, but
signals of drier weather appear possible by the late weekend with
more zonal flow.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...There continues to be a mix of
categories from VFR to IFR across northern New York and Vermont.
As flow turns more westerly with the slow eastward track of the
low, IFR chances will increase. Also, some thunderstorms have
formed at the low`s center and could occur in the vicinity of
RUT through 04Z. LLWS will continue to be a threat especially
with variable surface winds and stronger gradient aloft. After
12Z the threat of LLWS will diminish with CIGs rising rapidly
after 15Z.
Outlook...
Tuesday Night: Mainly VFR, with local MVFR possible. Definite
SHRA.
Wednesday: Mainly VFR, with local MVFR possible. Definite SHRA.
Wednesday Night: VFR. Chance SHRA.
Thursday: Mainly VFR, with local MVFR possible. Definite SHRA.
Thursday Night: Mainly VFR, with areas MVFR possible. Chance
SHRA.
Friday: Mainly MVFR, with areas VFR possible. Chance SHRA.
Friday Night: Mainly MVFR, with areas VFR possible. Slight chance
SHRA.
Saturday: Mainly VFR, with areas MVFR possible. Slight chance
SHRA.
&&
.EQUIPMENT...
The TYX radar is down until further notice after a hardware
failure occurred. Replacement parts have been ordered and will
be installed.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Boyd/Taber
SHORT TERM...Taber
LONG TERM...Danzig
AVIATION...Boyd
EQUIPMENT...BTV
|
