Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 260503
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1203 AM EST Sun Feb 26 2017

.SYNOPSIS...
A strong cold front will continue move eastward across the
North Country this afternoon and early evening. The leading edge
of the front will have strong gusty winds and heavy rain. Rain
will continue behind the front continuing the potential for ice
jams and river flooding through the weekend. Tonight, lingering
snow showers concentrated over the higher terrain will taper off
Sunday morning. More seasonable weather returns Sunday with
some light snow in the higher elevations before a quieter period
of weather to start the work week.

&&

.NEAR TERM /UNTIL 6 PM SUNDAY EVENING/...
As of 953 PM EST Saturday...Updates as of mid-evening include
massaging pops/weather and hourly temperature/dewpoint trends
per latest observations. Rain switched to snow a few hours
earlier than anticipated this evening as mid-level front
overtook the surface boundary and allowed wet-bulbing processes
to dominate in heavier pcpn cores. As a result, moderate/heavy
rainfall transitioned to a rain/snow mix or all snow in many
locales this evening with a wet slushy coating to a few inches
in spots. I`ve updated our estimated snow totals for this
evening before precipitation tapers off overnight, which shows
similar amounts to our prior forecast, though perhaps a tad
higher in elevated locales and in the northern Champlain Valley.
Mainly minor stuff, though quite the end to one of the
strangest weather days you`ll see for awhile. Primary surface
front has now cleared east of the forecast area so the threat of
stronger, gusty winds in our area has ended. Still, there are
several thousand without power across Vermont this evening from
prior gusts in the 35 to 45 mph range. As temperatures continue
to gradually cool overnight, some patchy black ice will be
possible on area roads as prior rainfall freezes. This will
occur mainly in areas outside the Champlain Valley so drive with
caution. Temperatures by sunrise Sunday mainly in the mid 20s
to lower 30s under modest west/northwesterly flow.

On Sunday, some gusty winds of 30kts or less are possible in
lingering PGF before subsiding in the afternoon. Drier air will
move in with slight ridging at the surface. Max temperatures in
decreasing cloud cover will generally be in the 30s with a few
spot readings around 40 in southern VT counties.

&&

.SHORT TERM /6 PM SUNDAY EVENING THROUGH MONDAY NIGHT/...
As of 318 PM EST Saturday...Ridging at the surface continues
Sunday night, but a mid level shortwave will near the
international border Monday morning. Models disagree how far
south the shortwave will reach, but with limited moisture
available, have kept only slight chance POPs throughout the
period, mainly for higher terrain near the international border.
With increased cloud cover possible from the shortwave and
generally moderating temperatures as low level flow becomes for
SW, expect min temperatures Sunday night to be in the 20s.
Increasing 500mb heights indicative of continued moderating
temperatures in SW flow on the NW edge of surface ridge will
have Monday and Monday night dry with max temperatures in the
40s and mins in the 20s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 318 PM EST Saturday...Tuesday the area will remain under
slight ridging aloft, but moisture and weak vorticity attempt to
move in from the south. NAM and GFS in agreement bringing
precipitation into at least the southern half of the forecast
area Tuesday afternoon, while ECMWF wait for developing low to
bring precipitation Tuesday night-Wednesday. This system
associated with deepening 500mb trough over the northern plains
states. Details of track of developing surface low and strength
continue to be under debate. Overall 12Z GFS and ECMWF show the
surface low to track near the international border, which could
start precip as rain through most of Thursday before the
associated cold front moves through. Lingering snow showers
possible late Thursday. Overall still time for models to focus
around a solution.

&&

.AVIATION /06Z Sunday THROUGH Thursday/...
Through 06Z Monday...Composite radar loop showing precipitation
over extreme northeast Vermont at this time will be east of the
region by 06Z Monday. Expecting mainly MVFR/VFR ceilings
overnight, with mainly VFR conditions expected after 14Z Sunday.
Expecting west-northwest surface winds to begin to gust at or
above 20 knots across the entire region by 14Z Sunday.

Outlook 06Z Monday through Thursday...

06Z Monday - 12Z Tuesday...Mainly VFR under high pressure.

12Z Tuesday - 00Z Thursday...VFR with chance MVFR/IFR rain
showers.

00Z Thursday - 00Z Friday...areas of MVFR in rain showers ahead
of a cold front.

&&

.HYDROLOGY...
As of 400 PM EST Saturday...Rivers seeing rises with snowmelt
and ice jams on northern rivers. Missisquoi River jams causing
high water at a few spots along that river and have issued a
flood warning for Franklin County along the river for the jams.
Great Chazy showing some ice impacts with locals reporting a jam
in place at Perry Mills but water finding a way through. East
Branch Ausable at Ausable Forks NY jam has moved downstream and
has come to rest near Chester NY with no effect according to
Emergency Management. Passumpsic river also at risk for ice jams
but no ice movement yet reported there. Ice jams possible
anywhere there is a constriction in the river such as a bend or
bridge abutment to stop ice movement.

Thunderstorms and rain moving into area will combine with
ongoing snowmelt produced by record setting temperatures to
transition this to an open water minor flood event. Have already
issued flood warnings for flooding for East Branch Ausable at
Ausable Forks and Otter Creek at Center Rutland to exceed flood
stage later tonight. Both gages only a couple feet below flood
stage at issuance. Watching Winooski basin for rain/snowmelt
flooding as well but holding off on warnings at the moment until
we see the rainfall amounts. Missisquoi also at risk of open
water flooding possibly at North Troy VT where ice is not
present. Lamoille River less of a flood threat as it is starting
at lower levels, and forecast to see mainly within-bank rises.

Most river rises overnight with crests after midnight into mid
day Sunday.

&&

.CLIMATE...
Daily high temperature records were broken or smashed once
again across the area today, with all-time February monthly
records being set at Burlington (72 F) and St. Johnsbury (64 F).
Incidently the 72F at Burlington today, along with the same
reading reached at Bennington, VT yesterday set new all-time
Vermont state records for February, quite an achievement.
Records for Burlington go back to 1884. For a full rundown on
all the records set today, please visit our website at
www.weather.gov/btv.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Flood Watch through Sunday evening for VTZ001>012-016>019.
NY...Flood Watch through Sunday evening for NYZ026>031-034-035-087.

&&

$$
SYNOPSIS...Deal/KGM
NEAR TERM...JMG/KGM
SHORT TERM...KGM
LONG TERM...Evenson/KGM
AVIATION...Evenson/WGH
HYDROLOGY...Hanson
CLIMATE...JMG



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