Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 221759
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1259 PM EST Thu Feb 22 2018

.SYNOPSIS...
Cloud cover will increase today as a weak system brings a chance
of snowfall to southern Vermont this afternoon. Clouds will
then decrease through the overnight hours with temperatures
returning to near normal values. Temperatures will then quickly
warm on Friday as another system moves toward the area.
Precipitation will build across the region late Friday morning
with a transition from snow to sleet to rain expected but no
impacts are expected with this system as it quickly exits the
region Friday night.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 1218 PM EST Thursday...Very minor update to capture latest
trends in temps/dwpts and winds. Still expecting a period of
light snow across Rutland/Windsor Counties between 18z-21z this
aftn...which is confirmed by latest radar trends. The
combination of deeper moisture and lift from 700mb fgen forcing
will help saturate low levels enough to produce this light snow.
Otherwise...a few flurries possible over central vt into the
high peaks with mostly cloudy skies prevailing. Temps holding
steady in the upper 20s to mid 30s.

Previous discussion below:
Temperatures have been slower to fall than originally expected
as quite a bit of mid and high level clouds continue to push
across the region. In addition, the majority of the cold air
advection seems to have lagged a bit behind the cold front with
Canadian observations showing temperatures just in the low 20s.
Skies will clear toward morning and as the temperatures at 850mb
and 925 mb continue to cool, our low temperatures should be
observed just after sunrise.

An impressive fetch of southwesterly flow aloft continues to
advect moisture from the Gulf of Mexico up toward the North
Country. The strong Bermuda High that brought record warmth to
much of New England yesterday has now retreated slightly to the
southeast but 850/700/500 heights still remain well above normal
for this time of the year. The way that the longwave pattern has
set up with the aforementioned southwesterly flow aloft will
continue to bring several short waves through New England over
the next several days. The first shortwave will push south of
Vermont this afternoon and a chance of snow will develop across
Windsor and Rutland Counties. Much of the moisture with this
system will be shunted pretty far south but some moisture will
wrap around the shortwave and bring some snow near the VT/NY/MA
border but Rutland and Springfield may see a dusting of snow
while the remainder of the forecast area remains dry.

Skies will clear on the backside of the shortwave tonight with
nice subsidence suppressing cloud cover. This will lead to a
true radiative cooling night where temperatures are expected to
drop into the single digits to mid teens across the forecast
area. Even with these colder temperatures, temperatures will
remain near or slightly above normal due in large part to the
anomalously high heights aloft.

Temperatures will quickly warm on Friday as warmer and wetter
air associated with another shortwave pushes toward New England.
Precipitation type will be the forecast challenge with this
system as temperatures across the board start well below
freezing and warm throughout the day. A transition from snow to
sleet to rain is expected as temperatures warm both aloft and at
the surface. There could be some pockets of freezing rain but
these look restricted to the higher elevations. Valley locations
within and east of the Green Mountains will likely see periods
of sleet linger through the afternoon as the cold air at the
surface will likely be difficult to scour out. Overall QPF looks
unimpressive with less than a tenth of an inch of liquid over
most locations with slightly higher amounts over the higher
terrain.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 445 AM EST Thursday...Friday night...most of the precipitation
will be tapering off in the evening as the best warm advection,
lift, and deeper moisture moves east rather quickly and a weak
occluded front moves though the region. Precipitation type will
be mainly rain as the column warms but still a bit problematic
in eastern VT where some pockets of freezing temps will linger
with light freezing rain. Still some uncertainty in temps being
a degree or two either side of freezing. Some of the higher
terrain above 2000 ft could see some snow showers by Saturday
morning as colder air aloft moves in. QPF will be light with
less than a tenth of an inch so not expecting much of either
freezing rain or snow. High pressure over Quebec and ridging
aloft moves into the region for Saturday afternoon and the first
half of Sat night before the next system in the form of an warm
and occluded front approaches with some increasing clouds late.
More below.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 445 AM EST Thursday...A rather strong and deepening low pressure
will track from CO through the western Great Lakes into James
Bay Canada through Sunday night. It`s associated occluded
frontal system and precipitation will move from southwest to
northeast into the North Country starting early Sunday.
Initially, it looks like it will be cold enough for an inch or
so of snow or sleet on the leading edge bute`ll be on the warm
side of that system as well as temperature profiles warm above
freezing right up through 850 mb so any mix/snow will change to
rain once again. The winds should be stronger on Sunday as we
see some SE downsloping developing. Anticipate 20-30kts with
gusts of 25-45kts along the western slopes of the Greens and the
northern slopes of the Adirondacks. It does look a little drier
and slightly cooler Monday through Wednesday with ridging aloft
and a NW flow as high pressure moves from the midwest to the
mid- Atlantic coast. There may be a few rain or snow showers
especially in the higher terrain with the NW flow later Monday
into Tuesday morning, but very light QPF. It will continue
warmer than normal through the period with high temperatures in
the upper 30s to mid 40s Sunday cooling a bit in to the 30s to
near 40 with lows in the upper mid 20s to low 30s Monday then
down in the 20s with a few teens Tue/Wed.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Through 18Z Friday...Mainly VFR conditions will prevail through
the TAF period with the exception of KRUT, where a quick shot of
light snow could temporarily reduce conditions to MVFR between
18Z and 21Z. As the majority of the precipitation from this
system will remain south of the forecast area, expect all other
TAF sites to remain VFR. Light northerly winds will continue
through the night and switch to southerly winds of up to 10 kt during
the morning hours. Through the afternoon, southerly winds will
increase to 10-15 kt with gusts up to 25 kts possible through
the early afternoon.

Outlook...

Friday Night: Mainly MVFR, with areas VFR possible. Chance RA,
Chance FZRA.
Saturday: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday Night: VFR. Chance SN.
Sunday: Mainly MVFR and IFR, with local VFR possible. Definite
RA, Definite SN.
Sunday Night: Mainly VFR, with local IFR possible. Chance SHRA,
Chance SHSN, Chance PL.
Monday: VFR. Slight chance SHRA, Slight chance SHSN.
Monday Night: Mainly VFR, with local MVFR possible. Slight chance
SHSN.
Tuesday: VFR. Slight chance SHRA, Slight chance SHSN.

&&

.HYDROLOGY...
As of 445 AM EST Thursday...The flood watch has been cancelled
as temperatures have dropped below freezing across much of New
York and Vermont this morning which has helped to reduce snow
melt runoff. Flooding associated with localized ice jams is
still ongoing across portions of Northern New York and northern
Vermont but latest hydrographs show most locations have crested
and are beginning to drop. There still may be some flooding
associated with ice jams today as ice jams release and re-develop
downstream but the greatest potential for flooding has ended.

&&

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

&&

$$
SYNOPSIS...Clay
NEAR TERM...Clay/Taber
SHORT TERM...Sisson
LONG TERM...Sisson
AVIATION...RSD
HYDROLOGY...Clay/Sisson/Neiles


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