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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 240223
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1023 PM EDT Fri Oct 23 2020

.SYNOPSIS...
A cold front will move through Saturday morning, which will
bring a few rain showers and falling temperatures through the
weekend behind the front. After a dry and seasonably cold
Sunday, wet weather will arrive by Monday morning across the
entire area. Temperatures will stay below normal during most of
next week.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 1020 PM EDT Friday...Updated pops again to better capture
broken line of rain showers with embedded rumbles of thunder
approaching the SLV. Thinking convection is limited acrs our fa,
as instability/dynamics are waning. Also, have bumped hrly
temps/dwpts up by several degrees, as MSS is crntly 71 and BTV
is holding at 68. Combination of southerly winds and increasing
clouds ahead of cold front is helping to hold temps steady,
before falling sharply after fropa later tonight into Saturday
Morning. Still anticipating some localized gusts up to 30 knots
acrs the SLV/dacks and parts of the CPV overnight before fropa.

Changeable wx anticipated acrs our cwa, as a sharp cold frnt
will swing thru the fa tonight into Saturday. The general idea
of best s/w energy passing to our northwest still holds, while
sharp convergence and good ribbon of mid lvl moisture with
boundary produces a band of showers from west to east acrs our
fa. This precip will impact slv after 04z, dacks btwn 06-08z,
cpv 08z-12z, and thru most of vt by 16z, besides some lingering
upslope precip. Overall qpf will generally be in the 0.05 to
0.25 range with highest values over the SLV. Have sharpened up
the pop fields overnight, along with making some minor
adjustments to hrly temps. Combination of southerly winds and
advancing clouds will keep temps on the mild side overnight,
until boundary sweeps through. Otherwise, fcst in good shape.


Previous discussion below
Was overall a very warm and breezy day today for the North
Country, with highs in the low to mid 70s across northern NY and
the Champlain Valley. Meanwhile east of the Greens, onshore
southerly flow led to persistent marine stratus which has kept
central and eastern Vermont in the upper 50s to mid 60s today.
Southerly winds with some gusts 15 to 25 mph this afternoon will
weaken some this evening, then strengthen again towards
midnight as a southwesterly low-level jet moves overhead.
Temperatures will decrease through the night tonight, but lows
will still be relatively mild in the mid to upper 50s for much
of Vermont and the Champlain Valley of NY. Low stratus clouds
over eastern Vermont are expected to once again thicken and
lower tonight. Meanwhile, a front will approach from the west
overnight which will spread some mid and low-level clouds over
northern NY during the early morning hours of Saturday. The
front will be somewhere in the vicinity of the Saint Lawrence
Valley around sunrise, thus lows will be colder in the Saint
Lawrence Valley than elsewhere Saturday morning. As the front
moves eastward during the late morning hours of Saturday,
temperatures will continue to drop over the northern Adirondacks
and the Champlain Valley, and high temperatures will be
observed early in the day before the boundary goes through.
There will be some rain associated with the frontal passage.
Rain will start shortly after midnight over northern NY, then
diminish into just some light showers as the front progresses
eastward into Vermont during the late morning hours. Despite the
expected showers with the frontal passage, Saturday will by no
means be a washout, and total QPF amounts will only be in the
0.01 to 0.25 inch range. Highest amounts (generally 0.10 to 0.25
inch) are expected over the Saint Lawrence Valley into the
northern Adirondacks, along with the higher elevations of the
Green Mountains. Lower amounts (0.01 to 0.10 inches) are
expected in lower elevations of the Champlain Valley and eastern
Vermont.

The front will clear the area by Saturday evening, and skies will
generally trend less cloudy overnight.  There may be some low-level
moisture trapped near the surface which would lead to some low-
clouds overnight despite drier air moving in aloft.  However,
expecting most of the cloud cover to dissipate towards sunrise,
which would lead to rapid nocturnal heat loss with light winds as
high pressure builds in.  Overnight lows Saturday night will be in
the mid 20s to mid 30s.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 326 PM EDT Friday...Sunday is shaping up to be the coldest day
of the fall thus far as cold air continues to filter in behind the
cold front that moved through the region on Saturday. After seeing
morning lows in the mid 20s to mid 30s, temperatures will struggle
to climb into the lower to mid 40s; even with filtered sunlight.
High pressure throughout the day should yield light winds and dry
weather but an increase in precipitation chances will be seen late
Sunday night as a shortwave tracks northeastward along the eastern
periphery of the positively tilted upper level trough.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 326 PM EDT Friday...A cold, rainy and snowy day is in store for
the North Country on Monday as a potent shortwave tracks across the
region. It looks like a burst of snow can be expected across
northern New York early Monday morning as all guidance shows the
vertical thermal profiles initially below freezing. As the morning
progresses, we will see a push of warm air advection between the 925
mb and 850 mb levels which may lead to a very brief transition to
freezing rain before changing over to rain. Snowfall looks less
likely to accumulate across Vermont given the timing of the precip
occurring after sunrise. Temperatures at the surface may hover
within a degree or two of freezing as precipitation starts but would
quickly changeover to rain with the only accumulations in Vermont
likely above 1500 ft. Even the higher terrain will transition to
rain by mid-afternoon. When all is said and done, a dusting to an
inch of snow will be common across northern New York with little to
no accumulation across Vermont. Rainfall totals will be pretty
decent given the strong dynamical forcing with anywhere from a
quarter to a half of an inch likely. Temperatures will be a little
tricky on Monday as rainfall and thick cloud cover will inhibit much
diurnal heating but a strong push of warm air advection should allow
our temps to rise into the mid 40s by late afternoon.

Rainfall will slowly taper off Monday night with another quick shot
of snow possible if temperatures can cool quick enough. This time,
no accumulating snowfall is expected as the duration of any snow
would be short and the intensity light. The remainder of the
upcoming week continues to look unsettled with a series of
disturbances tracking across the northeastern US. Each model run
varies from the last given that shortwaves are very difficult to
time and track in the extended period. Basically, periods of showers
(both rain and snow) look possible through next week as we see
temperatures remain around 10 degrees below normal.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Through 00Z Sunday...Currently VFR conditions across the
forecast area, except KMPV where marine stratus continues to
linger east of the Green Mountains. This has resulted in mostly
MVFR cigs at KMPV, though clouds may occasionally scatter out to
VFR during the next couple of hours before trending back down to
MVFR. Elsewhere, VFR conditions are expected to persist until
about 09z. At which time, a cold front will pass from west to
east, bringing scattered rain showers and area wide MVFR to IFR
cigs until 18z. Thereafter, a return to VFR conditions are
expected except at KSLK where lingering low level moisture will
keep MVFR cigs in place.

Southerly winds are expected to increase within the next couple
of hours, gusting up to 20-25 kts at KBTV, KRUT, KMSS, and KSLK
in advance of the approaching cold front. Gusts will end at
these locations after 12z. In addition, between 03-12z, LLWS is
expected as a SSW low level jet moves overhead.

Outlook...

Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. Chance SN.
Monday: Mainly MVFR, with local IFR possible. Definite RA.
Monday Night: MVFR/IFR conditions possible. Chance SHRA, Chance
SHSN.
Tuesday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Tuesday Night: Mainly VFR, with areas MVFR possible. Slight
chance SHRA, Slight chance SHSN.
Wednesday: Mainly VFR, with areas MVFR possible. Slight chance
SHRA, Slight chance SHSN.

&&

.MARINE...
A Lake Wind Advisory continues for southerly winds with gusts
15 to 25 knots today on the Lake. Gusts will increase this
evening through tonight to around 30 knots, peaking in the early
morning hours. Waves will be 1-3 feet today, building to 3 to 5
feet tonight after midnight. Winds will begin to diminish
around sunrise Saturday morning.

&&

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

&&

$$
SYNOPSIS...Duell
NEAR TERM...Duell/Taber
SHORT TERM...Clay
LONG TERM...Clay
AVIATION...Duell/Hammond
MARINE...Team BTV