Area Forecast Discussion
Issued by NWS Burlington, VT

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS61 KBTV 181739

Area Forecast Discussion
National Weather Service Burlington VT
1239 PM EST Mon Nov 18 2019

Freezing rain will move into southern and eastern Vermont this
afternoon with a mix of freezing rain and sleet moving into western
Vermont and northern New York during the evening and overnight
hours. This mix of precipitation will change over to snow prior to
sunrise on Tuesday and will gradually taper off during the afternoon
hours on Tuesday. Quieter weather is expected on Wednesday and
Thursday but another storm system will move into the region on
Friday. This system will likely bring a mix of rain and snow to the
North Country.


As of 1221 PM EST Monday...Overall forecast remains on track.
Temperatures have crept into the upper 30s to near 40 across the
Champlain Valley and into the St. Lawrence River Valley, where
partial clearing has been observed. As the coastal system moves
to our east, expect increasing moisture to allow clouds to build
back in as well as produce intermittent drizzle/freezing
drizzle. All else remains in good shape.

Previous Discussion...Temperatures overnight have been 10
to 15 degrees warmer than yesterday morning as warm air advection
coupled with increasing cloud cover stifling our cooling.
Clouds cover will continue to work into the region this morning
but weak and blocked flow has kept the clouds on the windward
(southern and western) slopes of the Adirondack and Green
Mountains. The coastal low developing well off the coast of
North Carolina and Virgina has tracked further east than the
guidance showed this time yesterday. The observed pressure falls
from the few buoys and coastal sites show the low will likely
continue to track to the northeast through the remaining
morning hours which should take this low well east of the
benchmark. This will likely yield very little precip working
into the North Country through the morning and afternoon hours
as the main moisture axis will be shunted eastward. Some wrap-
around precipitation will be possible across eastern Vermont
during the mid to late afternoon hours which looks like it
should fall as freezing rain. The big question across southern
and eastern Vermont this afternoon will be the degree of heating
at the surface. Any fluctuations a degree or two warmer than
the current forecast would likely yield a transition from
freezing rain to just a cold rain but the northerly flow
developing this morning should help replenish the cold air and
negate the latent heat release from the falling freezing rain.

Heading into the evening and overnight hours, things begin to get
even more interesting. A negatively tilted 850-500 mb trough will
move across the North Country with strong synoptic forcing and upper
level diffluence. The combination of these features will allow
precipitation to overspread the North Country between 8 and 11 PM.
Much of this precipitation will start off as freezing rain with
warmer air overrunning a below freezing surface. The thermal profiles
remain the most challenging aspect of the forecast as the placement
and timing of the upper level trough will impact the degree of cold
air advection and the ultimate transition from freezing rain to an
hour or two of sleet and eventually over to snow. Freezing rain
amounts are slightly less for the Champlain Valley given the
latest data with less than a tenth of an inch expected but up to
two tenths of an inch is still possible for southern and
eastern Vermont. It should be noted that the 06Z NAM has come
into very good agreement with the 00Z GFS and 00Z ECMWF in
regards to the precipitation tonight which begins to increase
our confidence in a mixed precipitation event happening through
the overnight hours.

It looks like most places will transition to snow before the
morning commute on Tuesday but the possibility of an icy layer
on the roadways with falling wet (8:1 to 10:1 ratio) snow will
create some very slick surfaces. Snowfall will taper off from
southwest to northeast throughout the day on Tuesday before
ending in northeastern Vermont by late afternoon. Overall
snowfall accumulations look to range from 1-3 inches with some
local amounts near 4 inches across the northern Green Mountains.


As of 410 AM EST Monday...Tuesday night and Wednesday will be
relatively quiet in relation to the near term. A negatively tilted
upper level trough will pass to our South during these 2 periods.
Will be tough to rule out some light snow showers with the upper
trough and associated vorticity advection nearby. Temperatures will
warm a bit, but still remain below seasonal normals. Mainly cloudy
conditions are anticipated.


As of 410 AM EST Monday...Wednesday night and Thursday will trend
drier with surface and upper level ridging building over the north
country. Headed into Thursday night, a low pressure system will lift
northeastward from the Great Lakes into Quebec. Will have chance for
rain showers with this feature on Friday, though nothing very
significant with best forcing remaining closer to parent low well to
our North. Better chance for precipitation in our area will come on
Friday night as surface cold front crosses the area and we`ll have
better forcing with the surface feature. At this time looks like
precipitation would start out as rain and then change to snow or
snow showers with cold air advection behind the surface front.
Pretty decent upper level trough and shortwave energy also passing
through on Friday night. Showers will end during Saturday morning.
The rest of Saturday heading into Saturday night would mainly be dry
with some weak surface ridging. Headed into Sunday a weak clipper
type low crossing the North Country will bring another chance for
light snow showers. Surface and upper level ridging will return once
again for Monday and Tuesday. Very changeable patterns in the
extended portion of the forecast will keep the weather active.


Through 18Z Tuesday...Pockets of VFR/MVFR with a stratus deck
lifting north. Anticipate this to continue through 00Z before
ceilings trend below 2500ft agl across most terminals with
periods of DZ/FZDZ. Areas of FZRA, IP, or a mix are expected at
most terminals after 00Z-03Z. A transition to snow around 09Z to
12Z. In heavier precipitation and snow, visibilities of 1 to 4
SM is likely along with ceilings of 500-1500ft agl. After 15Z,
precipitation lifts north of the region with gradual
improvements in ceiling and visibilities. Winds become 5 knots
or less preferring north to northwest, but often calm to


Tuesday Night: MVFR/IFR conditions possible. NO SIG WX.
Wednesday: Mainly MVFR, with local IFR possible. Slight chance
Wednesday Night: Mainly VFR, with areas MVFR possible. Slight
chance SHSN.
Thursday: Mainly VFR, with areas MVFR possible. Slight chance
Thursday Night: Mainly VFR, with areas MVFR possible. Likely
SHRA, Chance SHSN.
Friday: Mainly MVFR, with areas IFR possible. Likely SHRA, Chance
Friday Night: Mainly VFR, with areas MVFR possible. Chance SHSN,
Likely SHRA.
Saturday: VFR. Slight chance SHSN.


VT...Winter Weather Advisory from 6 PM this evening to 1 PM EST
     Tuesday for VTZ001>009-016>018.
     Winter Weather Advisory until 1 PM EST Tuesday for VTZ010>012-
NY...Winter Weather Advisory from 6 PM this evening to 1 PM EST
     Tuesday for NYZ027-028-030-031-034-035.


NEAR TERM...Clay/Haynes
LONG TERM...Neiles
AVIATION...Haynes is the U.S. government's official web portal to all federal, state and local government web resources and services.