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227
FXUS61 KBTV 290918
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
418 AM EST Sun Nov 29 2020

.SYNOPSIS...
High pressure nudging northward into the region today will provide
the North Country with a dry end to the weekend with increasing
sunshine and temperatures slightly above normal. Fair weather will
be short-lived though as a strong low pressure system will move into
the region Monday and dominate our weather through at least mid-
week. The most impactful period of weather will be Monday mid-
morning through the evening with rain becoming widespread through
the day and a period of gusty east to southeast winds in the
mountains late Monday into Monday evening. Cooler and showery
conditions are expected late Tuesday through the rest of the work
week.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 417 AM EST Sunday...Pick of the week for weather will certainly
be today as high pressure over the central Appalachians nudges
northward and finally kicks out the low level moisture that has
plagued us the past several days. We should see morning clouds
across central/northern portions of the forecast area gradually
erode from south to north this morning the sunny skies and slight
above seasonal temperatures develop for this afternoon. Look for
highs to range through the 40s with the warmest values in the upper
40s across the wider valleys. Dry conditions will persist tonight as
well, but we`ll see some increasing mid/high clouds shift in through
the night ahead of our next system. Low temps will be quite tricky
as winds decouple outside of the wider valleys, and low/mid-level
warm air advection increases through the night. Thinking temps will
hold in the mid/upper 30s in the Champlain/St. Lawrence Valleys with
upper 20s to lower 30s elsewhere.

Looking ahead to Monday and Monday night, the forecast remains on
track as a northern stream trough will phase with rich southern
stream GOMEX energy to develop a dynamic storm system over the south-
central Appalachians Monday morning. Consensus storm track of global
and mesoscale models brings the surface low northward into central
PA early Monday afternoon, and north of Lake Ontario by Monday
night. This is perhaps a slight westward nudge from the 12Z NWP, but
only slightly and overall does not change the forecast significantly
and still places the North Country on the warm and windy side of the
storm. Main impacts continue be a swath of moderate rainfall,
perhaps starting as a very brief wintry mix in the colder hollows,
and gusty east-southeasterly downslope winds. Precipitation will
develop early Monday from southwest to northeast becoming widespread
by early afternoon along a warm front passage. No concerns with
ptype as strong warm advective processes support temps well into the
upper 40s to mid 50s. Overall amounts for the 24-hour period will
generally range from 0.50-0.75" with localized amounts to 1" in the
southeast upslope regions of the Adirondacks and southern Greens.

Late Monday into Monday night as a mid-level dry slot works into the
region precipitation will become more showery in nature and areal
coverage will decrease from west to east. This will be the period
where winds could briefly gust up into the 30-45mph range along the
western slopes as the core of strong 925-850mb jet passes just east
of the region. On the western periphery of the jet core, winds at
925mb peak up to 50-60kts for a very brief period from about 21-01Z,
and coincides with the dry slot working in. Details remain very
fuzzy whether the low levels will be unstable enough to support
mixing these winds to the surface, and while we continue to lean
towards more stability, the potential still remains for some brief
gusts to 45 mph in the typical southeast downslope locales such as
Underhill, Jericho, South Lincoln, Ripton, and especially Mendon and
Clarendon. Lows Monday night won`t drop much, holding in the low 40s
west to around 50 east, and we could be looking at some record high
min temps for Dec 1.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 417 AM EST Sunday...Temperatures are still tricky on Tuesday,
as deep mixing will boost temperatures and counteract cooling aloft
somewhat. With the very mild/record breaking minimum temperatures,
we will be off to a warm start. The warmest air will be towards the
northeast, so unusually the warmest conditions may be in the
Northeast Kingdom, with highs possibly pushing 60 if the mid-level
dry slot works its way towards the low-levels. Much of the period
will be dry with some breaks in the clouds possible, with the best
forcing for ascent to our west and moisture remaining to our east.
However, I have maintained chances for rain showers with questions
about how frontogenetic forcing develops over the region which
would be the focus for widespread showers. Any rain showers,
which have highest chances in northern New York, should change
over to snow showers gradually Tuesday night in the Adirondacks
and Greens as sub-freezing temperatures aloft drop closer to the
ground, minimizing the melting layer. So expect the snow
showers to initially fall with surface temperatures well above
freezing, and in concert with warm road temperatures, any
impacts will likely be due to reduced visibility. Temperatures
should be much cooler Tuesday night with temperatures falling
back to the upper 20s to mid 30s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 417 AM EST Sunday...On Wednesday we will see unsettled weather
continue as we remain close enough the occluded low pressure area,
now near Ottawa, to see plentiful low-level moisture and clouds.
Mixed signals for lake- effect snow showers exist over portions of
southern St. Lawrence and Essex counties in New York. The
instability and moisture will be in place, but wind direction is the
question as some data suggests low- level flow will be southerly
rather than the necessary southwesterly direction. However, by later
in the day, better consensus that winds will go more westerly as the
low drifts northeastward. Upper-level shortwave energy will help
trigger more snow showers and lake- enhanced snow. These snow showers
should diminish by Thursday morning, with best potential for light
snow accumulation in the Adirondacks, with the specific area to be
fine tuned as we get into the higher resolution model data.
Elsewhere, lower chances of precipitation but scattered instability
snow showers, or rain in the lower valleys, will develop and move
through. With the upper-level low lifting northeastward, the general
idea would be best chances of snow showers should be in northern New
York during the day and shift into Vermont Wednesday night. Lower
chance of precipitation is expected on Thursday, with better chances
of some light snow on Friday. Temperatures from Wednesday through
Friday should tend to be near normal, or a little above normal at
night given propensity for cloud cover. Then a more significant
system, which will crash along the Pacific northwest coast tomorrow
night, is poised to finally reach our area sometime on Saturday.
Unfortunately for snow lovers, all indications at this time are for
another rain event, perhaps ending as snow in the mountains. Stay
tuned!

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
Through 06Z Monday...Mainly FEW-BKN VFR ceiling are expected
through 15Z, trending to SKC thereafter. Only exceptions will
be KSLK where MVFR will persist through 15Z, then lift north to
KMSS briefly for a few hours this afternoon. Winds will be generally
light south to southwesterly from 4-10 kts through the period.

Outlook...

Monday: Mainly VFR, with local IFR possible. Definite RA.
Monday Night: Mainly MVFR, with local IFR possible. Likely SHRA,
Definite RA.
Tuesday: MVFR. Chance SHRA.
Tuesday Night: Mainly VFR, with areas MVFR possible. Chance SHRA,
Chance SHSN.
Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA.
Wednesday Night: Mainly MVFR, with areas VFR possible. NO SIG WX.
Thursday: Mainly VFR, with local MVFR possible. NO SIG WX.

&&

.CLIMATE...
Below are the record high minimum temperatures for December 1st that
have the potential to be broken.

KBTV     KMPV     K1V4     KMSS     KPBG     KSLK
47|2001  45|2001  45|2001  40|2016  47|2001  46|1914

&&

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

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Lahiff
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Lahiff
CLIMATE...