000
FXUS61 KBTV 132026
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
326 PM EST Tue Nov 13 2018

.SYNOPSIS...
Low pressure moving along the East Coast will produce a mix of
rain and wet snow across the North Country today. Snow
accumulations will range from an inch or two in the Champlain
and Saint Lawrence Valley to 3 to 6 inches in the mountains of
Vermont and northern New York. Blustery and colder conditions
follow this system tonight into Wednesday, with highs mainly in
the upper teens to upper 20s. Another coastal system will impact
our region on Friday into Saturday with a mix of rain and snow
likely.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 123 PM EST Tuesday...Have updated forecast to cancel the
remaining winter storm warning/advisories for our forecast area.
Main precipitation has moved off to the east, but the potential
for some light showers continues during the day as magnitude of
CAA increases. Any additional accumulations would remain under
an inch at all but the highest summits. Previous forecast on
track.

Previous discussion below:
Winter storm warnings continue for northern Vermont, including
the Northeast Kingdom for 4 to 8 inches of wet snow. Meanwhile,
winter weather advisories continue for the central/southern
Green Mountains in VT and northern Dacks in NY for 3 to 6 inches
of wet snow. Meanwhile, a dusting to an inch or two of slushy
wet snow is possible across the cpv/slv. Given timing of
expected heaviest snowfall, a difficult morning commute is
likely with poor visibilities along with snow covered and
slippery roads, especially above 1000 feet. The heavy wet snow
will have the potential to cause isolated to scattered power
outages.

An extremely challenging snowfall forecast continues across our
cwa today, especially in the valleys below 1000 feet where
current temps are holding in the mid 30s. Little overall change
in forecast occurred with this package, other than to sharpen
west to east qpf gradient and trim back snowfall amounts over
the slv/western dacks. Fast/progressive system with open
circulation will result in qpf ranging from 0.10 to 0.20
slv/western dacks to 0.30 to 0.50 cpv to 0.50 to 0.75 for
eastern VT. These type of open wave and fast moving systems
typical under perform in the qpf department across our cwa,
especially western sections.

Current thinking is a band of moderate to briefly heavy precip
will lift from south to north across most of VT and the eastern
Dacks btwn 10z-16z this morning, per latest radar trends. This
band of precip will have enough dynamics to cool the column just
enough to produce a period of wet snow, even into parts of the
cpv. Albany, NY started at 42f, but heavier precip arrived and
sfc temp cooled to 34f with snow falling, expect similar
scenario to occur at Rutland/Middlebury/BTV. The tricky part for
the cpv, including the BTV area how much accumulates given warm
sfc temps. Thinking very little near the water front, but a
quick slushy inch or two is possible near the airport into the
Essex/Williston/ and Jericho areas.

However, if this strong band stays south, then little snow
accumulation would be anticipated in this area. The northern
dacks and mountains of central/northern VT should stay cold
enough for all snow above 1000 feet. The best 850 to 700mb fgen
forcing and associated uvv`s lifts from south to north across
our central/eastern cwa btwn 10-16z today. Once this better uvv
couplet lifts northeast of our fa, expect temps to warm back
into the mid/upper 30s with a mix of light rain/snow depending
upon elevation. As precip tapers off expect snow levels to climb
around 1500 feet, before winds shift to the west/northwest by
21z and cold air advection develops. Given the progged 925mb to
850mb 0c line bisects our southern cwa during the event, the
heaviest axis of qpf/snowfall should occur 25 to 50 miles north
of this line, over central VT.

Given very fast/progressive flow aloft with no closed 7h/5h
circulation to advect deeper Atlantic moisture on the backside,
thinking precip ends quickly from west to east btwn 18z-21z
today. A brief period of upslope snow showers are possible as
strong low level caa occurs and squeezes out remaining moisture
in the column this evening. However, moisture within the
favorable snow growth region is limited, which will minimize
additional snowfall amounts.

Strong low level caa develops on brisk west/northwest winds
tonight, as 925mb to 850mb temps crush into the -10c to -16c
range by Weds morning. Lows will range from the single digits
summits to l/m 20s cpv. Expect wind chill values near 20 below
summits to single digits and teens on Weds morning. A cold and
dry day is anticipated on Weds. However, soundings show lake
instability to be extreme off Lake Champlain, so anticipate
clouds downwind in the BTV area, along with maybe a few
flurries/light snow showers. The missing element for snowfall is
moisture. Highs teens to mid/upper 20s with brisk northwest
winds prevailing.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 323 PM EST Tuesday...On Thursday, high pressure will move
eastward and away from our area. Despite increasing clouds, our
forecast area will remain dry with temperatures cooler than
normal by about 15 degrees. Next system will be approaching from
the southwest on Thursday night, spreading clouds and light
snow from south to north across our area after 00z. A low
pressure system will track from the Ohio river valley off the
delmarva peninsula on Thursday, then along the New York and New
England coasts on Thursday night through Friday. It will be
centered very close to Cape Cod by 18z Friday. Friday night it
will lift even further off to the northeast and away from the
region. During this time period, we will have light snow with
some light rain mixing in in the valleys for Thursday night and
Friday. The best chance for light snow will be from about 10 pm
Thu to 2 pm Fri. As the low lifts further northeastward and away
from our area, light snow showers will become more
orographically enhanced with the flow becoming northwesterly,
but will be ending as we lose deeper moisture. We will have
highs in the 30s and lows in the 30s from Thursday through
Friday night. First thoughts about amount of precipitation is
between three and seven tenths of an inch of liquid
precipitation. Initial thoughts at snowfall totals is 3-7 inches
of snow with the highest amounts across our southern Vermont
zones and along the spine of the Greens. There is still lots of
uncertainty this far out, especially with track of the low. Both
GFS and ECMWF currently have the low track pretty tight in
along the New England coast. If the low tracks closer to our
area, we may have to mention mixed precipitation as well. Right
now feel that it will be mostly snow with a bit of a mix of
rain.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 309 PM EST Tuesday...The active weather pattern we have
been in will continue for the remainder of the extended period
as several impulses travel through fast west-east flow aloft.
Clouds and scattered showers will linger throughout the day
Saturday despite weak upper-level height rises. Anticipate these
showers to stay mainly confined to the higher terrain.
Temperatures should warm towards more seasonable values with
highs in the upper 30s to around 40 in the valleys and low to
mid 30s across the higher terrain.

Model consensus is poor on the Sunday system with GFS more
progressive and wet compared to the ECMWF solution. At this time
have just gone with a chance of precipitation...with the
greatest likelihood for northern New York where they could see
some lake enhancement. Quiet but cloudy weather settles briefly
on Monday before a weak clipper system approaches for Tuesday.
ECMWF/GFS agreement is much better on this system so have
increased chances for precipitation. At this time, guidance
suggests that temperatures should stay cold enough Sunday
through the remainder of the extended to be supportive of all
snow across the area. No real block busters expected during this
period but certainly accumulating snowfall is possible,
especially across the high terrain.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
Through 18Z Wednesday...Ceilings will slowly improve, as well
as visibilities as light snow ends across our area. Winds will
shift to the northwest this afternoon and become breezy at times
this evening at 15 to 25 knots. Expect vfr conditions by 00z,
except lingering mvfr cigs at mpv/slk. A few mountain snow
showers are possible this evening. As colder air moves over the
relatively warmer Lake Champlain waters, anticipate additional
clouds with potential mvfr cigs to develop at btv after 06z this
evening.

Outlook...

Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: Mainly VFR, with local MVFR possible. Chance SN.
Friday: Mainly MVFR and IFR, with areas VFR possible. Definite
SN.
Friday Night: Mainly MVFR, with local VFR possible. Chance SHSN.
Saturday: Mainly MVFR, with areas VFR possible. Chance SHRA,
Chance SHSN.
Saturday Night: Mainly VFR, with areas MVFR possible. Chance
SHSN.
Sunday: Mainly VFR, with local MVFR possible. Slight chance SHSN.

&&

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

&&

$$
SYNOPSIS...Taber
NEAR TERM...RSD/Taber
SHORT TERM...Neiles
LONG TERM...LaRocca
AVIATION...Neiles