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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 142354
AFDBTV

AREA FORECAST DISCUSSION
National Weather Service Burlington VT
654 PM EST Fri Dec 14 2018

.SYNOPSIS...
Seasonably mild and generally quiet weather continues into
Sunday under variably cloudy skies and a brief window of showers
this evening as a weak front moves across the area. A stronger
cold front pushes through the area on Monday with a renewed
threat of snow showers with colder air returning to the region
by the middle of next week.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 605 PM EST Friday...Water vapor shows short wave energy
and ribbon of slightly higher mid level moisture streaming
across northern NY into VT this evening. This moisture and
dynamics is helping to produce a band of mostly light rain, with
occasional moderate rain being reported at MSS. Have expanded
likely/cat pops mainly along and north of a KOGS to SLK to MPV
line thru this evening with some downslope shadowing likely
across the cpv. KCXX VAD shows 30 to 40 knots 925mb to 850mb
winds from the southwest ahead of approaching trof. Otherwise,
highest qpf of 0.10 to 0.20 will be near the international
border, with some mix of snow toward the summits and across the
northeast Kingdom of VT. Based on thermal profiles and summit
temps, expect snow levels around 3500 to 4000 feet, except lower
across the NEK, because of lingering pocket of 925mb to 850mb
thermal profiles below 0C. Otherwise, temps hold mainly steady
overnight in the mid 30s to near 40f with southerly winds,
clouds and precip. Expect most of the precip to end across
northern VT by 03z, which is covered nicely in forecast.


Previous discussion below:
Cloudy skies abound across the area as of mid afternoon as
southerly flow remains established in advance of a weak northern
stream trough approaching from southern Ontario. Modest
dynamical forcing on the front end of this feature should be
enough to spark a 3-6 window of scattered/numerous light showers
across our far northern counties into the evening hours and as
such highest pops (40-60%) will be carried in this area
accordingly. Further south just a stray sprinkle will be
possible. Thermal profiles continue to support mainly liquid for
p-type, but a few spots in the higher northern terrain and in
portions of far northeastern VT may see an occasional mix with
snow. Any accumulations will be minimal however. Temperatures to
hold fairly steady in the 30s to around 40 overnight before
falling slightly toward sunrise as associated weak cold front
crosses the area switching winds to light west/northwesterly.

Other than a few lingering sprinkles/light snow showers across the
far north Saturday morning mainly dry and quiet weather continues
into Saturday night as surface high pressure bridges across southern
Canada. Variably cloudy skies with occasional breaks to remain the
rule as temperatures remain fairly close to mid-December seasonal
norms (lows 15 to 25 and highs in the 30s).

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 237 PM EST Friday...An upper level cutoff low will be
tracking up from the Gulf Coast as an inland system Sunday.
Widespread rain across the southeast will deplete the system of
moisture as it heads towards New England. Some light precip may
make it into southern Vermont Sunday afternoon but at the same
time a northern stream upper level trough will be digging
through the Great Lakes. That should quickly push the inland
runner offshore. The combination of the inland runner pulling
offshore, and the advancing upper level trough should bring some
precipitation to the North Country generally by mid day on
Monday. The upper level support and dynamic cooling Monday
should lead to modest orographic snowfall with the western
slopes seeing 1-3 inches of new snow.

Temps should be a few degrees above normal with highs in the
mid to upper 30s and lows overnight should only fall to the
upper 20 to low 30s which is well above normal for this time of
year. Monday afternoon and evening expect temps to start to fall
as we get under the influence of cold air advection and lows
fall much closer back to near normal with lows in the teens to
low 20s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 237 PM EST Friday...High pressure builds in on Tuesday
and through the middle of the week the forecast looks pretty
quiet until the end of the week as the next system moves in.
Tuesday and Tuesday night certainly seem to be the coldest days
as we stay under cold air advection and temps sit below normal
for mid December. Expect highs in the teens to 20s with lows
Tuesday night in the low teens to single digits. The high
pressure shifts east of the region Wednesday and southerly flow
starts to push warm air advection back into the region on
Wednesday and Thursday.

Heading into the weekend the forecast remains fairly murky as
to exactly what will happen. The general idea as that an upper
level trough will develop on the lee side of the Rocky`s and
start tracking across the eastern half of the CONUS. The
question ends up being where does the surface low develop and
how does it materialize. For the time being I`ve leaned towards
the GFS solution largely based on the idea that the northern
stream trough through this winter has been stronger than the
southern stream counterparts. Thus I`d lean more towards the
idea we get a clipper type low that develops and brings modest
snow to the North Country Friday night into Saturday. Still
plenty of details to be worked out though before any of that
happens.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Through 00Z Sunday...Predominantly MVFR conditions will
continue through 12Z as a shortwave aloft moves through
overnight. Northern NY terminals along with KBTV seeing some
light to moderate rain showers move through, which are expected
to taper off between 02Z and 06Z. May see some isolated and
temporary IFR ceilings/visibilities at KMSS and KSLK between now
and 12Z, however expecting general improvement to widespread
VFR by 18Z.

5-15 kt southerly/southwesterly winds will trend lighter
overnight (3-10 kts) and become westerly/northwesterly after
12Z. The exception will be the Champlain Valley including KBTV,
which may see southerly gusts to 25 kts continue through 04Z.
Also have included some marginal LLWS in the Rutland TAF through
08Z with light southeasterly winds at the surface and a 35 to
45 kt southwesterly jet aloft.

Outlook...

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

&&

.MARINE...
As of 235 PM EST Friday...A Lake Wind Advisory remains in
effect tonight. Southerly winds, generally in the 15 to 25 knot
range with occasional gusts to 30 knots are expected this
evening before slowly abating later tonight. These winds will
create choppy to rough conditions on open waters and in
bays/inlets with open southerly exposures. Caution is advised
for those with recreational interests on the water tonight.

&&

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

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG/Taber
SHORT TERM...Deal
LONG TERM...Deal
AVIATION...RSD
MARINE...JMG