000
FXUS61 KBTV 071426
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
926 AM EST Thu Dec 7 2023

.SYNOPSIS...
Colder than normal temperatures continue today with scattered
light snow showers across northern New York. A warming trend
begins Friday and continues through the weekend with
temperatures climbing well above normal, especially on Sunday. A
potentially strong storm system will move into the region
Sunday afternoon and evening, bringing rain and gusty winds
before ending as snow Sunday night into Monday. While some area
rivers could approach or exceed bankfull Sunday night into
Monday, significant flooding is not expected.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 925 AM EST Thursday...No changes needed to the forecast
at this time. An elongated area of shortwave energy on the
leading edge of an upper ridge over the central CONUS is
producing some light snow across central New York and some of
this will drift into portions of the North Country today, but
based on radar trends and latest CAMs the activity will be very
light with low accumulations of just a dusting to perhaps a half
inch. The previous forecast has all this covered very well.
Previous discussion follows.

This morning, a shortwave trough slides southwest of our
region, bringing clouds and scattered snow showers to areas
mainly south and west of the Champlain valley where there is
better lift and moisture. With temperatures in the mid 20s to
low 30s, only a coating up to an inch of snow is expected. For
areas east of the Adirondacks and across Vermont, indications
are that after a cloudy start to the day, sunshine would return
by the late morning into the afternoon hours as the 925-700mb
level RH values fall to 30-50 percent range. However,
temperatures will remain unseasonably chilly in the 20s thanks
to a 1020mb surface high nosing in from Quebec and reinforcing a
pocket of -8 to -11C 925mb temperatures. For reference, typical
highs for early December across our region are in the mid to
upper 30s.

Heading into the overnight hours, the relative clear skies east of
the Greens as well as the albedo effect of the extensive snow cover
there will allow temperatures to plummet quickly into the single
digits, with a few negative readings across the Northeast Kingdom.
Cloud cover will be increasing across the Champlain Valley, so
expect mainly teens for overnight lows there and low to mid 20s
across the St Lawrence Valley. Snow showers could also linger across
the western zones into the southern Greens for a part of the
overnight hours, but expect a mainly quiet night of weather.

On Friday, a warming trend begins with temperatures moderating to
seasonal values. Upper ridging begins to build in with a 1024 mb
surface high sliding to our east during the day. It will be dry with
a mix of sun and clouds. High temperatures would generally be in the
30s across the region, with upper 30s to lower 40s possible for
portions of the Champlain and St Lawrence valley. Apparent
temperatures would be chillier with a southeast breeze but it should
feel relatively more comfortable to be outdoors compared to earlier
in the work week.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 350 AM EST Thursday...Quiet/dry weather this period as surface
high settles into the western Atlantic while upper ridging builds
into the region with winds trending steady south over time. This
will lead to significantly moderating temperatures with highs on
Saturday in the 40s to locally near 50 in the SLV with corresponding
lows Saturday night holding mild from 35 to 45.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 350 AM EST Thursday...The most impactful system of the 7-day
forecast to then affect the region Sunday into Monday.
Deterministic/ensemble solutions have begun to settle onto a
common theme, essentially painting a picture of a strong frontal
zone accompanied by a weak wave of low pressure riding
northward along the boundary through the region. These trends
now suggest any higher wind threat should be fairly limited.
However, copious moisture streaming northward along/ahead of the
front in combination with excellent dynamical forcing/upper
support should still produce steady moderate to occasionally
heavy rainfall across the region by Sunday afternoon/night. A
mix of blended QPF progs from favored output suggests a
widespread 1-2 inch event with scattered totals around 2 to 2.5
inches across southern counties, which will likely prompt
significant rises on area rivers due to snowmelt and runoff.
Ensemble hydrological output maintains higher probabilities of
several rivers at least nearing or exceeding bankfull by Sunday
night/early Monday so this will need to be monitored. However,
major flooding is not expected. Additionally, given the
relatively shorter duration of this warmup, the higher
elevations above 1500 feet will likely keep a good portion of
the existing early season snowpack, but significant settling is
certainly expected as rain will occur even at summit levels
Sunday afternoon/evening. As colder air streams in on the back
side of the boundary Sunday night, rain will likely change to
wet snow with early estimates and existing analogs suggesting a
few inches will be likely in the northern mountains with perhaps
a slushy inch or so in the broader northern valleys before
precipitation tapers off Monday morning. High temperatures to
run quite mild on Sunday (45 to 55) before values settle back
toward more seasonal values by later Monday/Monday night as
conditions trend dry.

Thereafter, a fairly quiet work week appears in store with
seasonably cool temperatures and mainly dry weather. A weak northern
stream clipper-type low may track through the region Wed/Wed night
with some scattered snow shower activity as suggested by GFS/ECMWF
deterministic output, but any accumulations should be minor. Daily
highs to generally run in the upper 20s to mid 30s with overnight
lows 15 to 25 or so.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Through 12Z Friday...Low clouds have scattered out across the
northern New York terminals and remaining Vermont terminals with
MVFR ceilings will improve to VFR by 14z. A deck of mid- level
clouds arrive from the west by mid morning, leading to another
round of MVFR ceilings for the NY terminals by 18-21z. This
would also be accompanied by isolated to scattered snow showers
for KMSS and KSLK from 21z onwards but little to no reduction in
visibility is expected. Winds will generally be variable and at
or below 5 kt for the TAF period.

Outlook...

Thursday Night: Mainly VFR, with areas MVFR possible. NO SIG WX.
Friday: Mainly VFR, with local MVFR possible. NO SIG WX.
Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Sunday: Mainly MVFR, with areas IFR possible. Chance RA.
Sunday Night: Mainly IFR, with areas MVFR possible. Windy with
gusts to 30 kt. Definite RA.
Monday: Mainly MVFR, with local IFR possible. Likely SHRA, Chance
SHSN.

&&

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

&&

$$
SYNOPSIS...Chai
NEAR TERM...Chai/Lahiff
SHORT TERM...JMG
LONG TERM...JMG
AVIATION...Chai