Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
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FXUS61 KBTV 192330
Area Forecast Discussion
National Weather Service Burlington VT
630 PM EST Sun Feb 19 2017
A weak cold front and associated upper level disturbance will
move southward from southern Quebec across Vermont and northern
New York overnight. This system will usher in colder air, along
with a few flurries, mainly across the northern mountains. High
pressure will build eastward from the Great Lakes providing more
seasonable temperatures and dry conditions for Monday and
Monday night. Calm winds and clear skies should make Monday
night the coldest of the week, with overnight lows in the single
digits and low teens. A quick moving low pressure system will
bring a period of rain and localized mixed precipitation to the
region Tuesday afternoon into Tuesday night. Mild temperatures
are then expected for the remainder of the week. The potential
exists for widespread precipitation, mainly in the form of rain,
and breezy conditions with low pressure passing to our west
Friday night into Saturday.
.NEAR TERM /THROUGH MONDAY NIGHT/...
-- Changed Discussion --As of 630 PM EST Sunday...Minor adjustments needed to the
previous forecast this evening, mainly to match up with current
observational trends. Still fairly warm out there with a lot of
locations hovering in the low/mid 40s and with clouds thickening
and winds keeping up it`ll take a little longer to drop below
40. Frontal boundary dropping southward through the
international border this hour has produced some weak radar
returns on upstream Canadian radar but it`s very spotty.
Adjusted precip chances down a bit and mentioned more of an
isolated/scattered nature to it which will likely be in the form
of sprinkles through midnight, with maybe some flurries and/or
light snow showers across the highest terrain thereafter. Little
to no snow accumulation is expected with early morning lows
still on track to be in the low/mid 20s. Have a good evening.
Previous Discussion...Another mild mid-February day across
the North Country with many locations reaching the upr 40s to
lower 50s earlier this afternoon. We`ve seen variably cloudy
conditions, associated with a northern stream trough and mid-
level height falls which are ongoing along the intl border. That
said, the best deep- layer convergence is focused across nrn ME
with a lead vort max, and we are mainly left with the weak
frontal boundary across srn Quebec, which will settle into our
region overnight. Some weak reflectivity returns have been noted
along the frontal boundary per McGill and Franktown radars in
Quebec and Ontario, respectively, and high-res models show that
activity across mainly our higher terrain areas between 00-06Z
Monday. Based on upstream trends and absence of deeper forcing
mechanisms, only expecting a few hundreths liquid equiv. for the
higher summits tonight, and kept wording as flurries, with a
passing valley sprinkle also possible. NW-N winds will continue
at 10-12mph overnight, and increasing low-level CAA will allow
early morning lows to reach the low-mid 20s in most areas.
Monday and Monday night will feature relatively tranquil weather
as sfc high pressure builds across from the northern Great Lakes
and northern Ontario. Anticipate increasingly sunny conditions
by Monday aftn with highs in the low-mid 30s. Winds will remain
northerly around 10 mph. It appears we`ll have good radiational
cooling conditions much of Monday night, likely yielding our
coldest temperatures of the week. May see some cirrus moving in
from the west toward daybreak, but light winds and dry deep-
layer conditions should yield lows 10-15F in the Champlain and
St. Lawrence Valleys, and in the single digits elsewhere. May
see a few readings below zero across far ern/nern VT, including
around Island Pond, Vermont.
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.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 336 PM EST Sunday...Tuesday begins with a full latitude
ridge from northern Quebec all the way south to FL associated
with high pressure along the east coast of North America.
A fast moving warm frontal system and short wave energy in the
westerly flow aloft along with narrow and weakening ribbon of high
and mid level moisture will produce a narrow axis of rain/snow/mix
of light precipitation Tue afternoon and night. Thermal profiles
still showing mostly rain in the valleys but a mix of precipitation
possible in the Adirondacks and Green Mountains east. QFP will be
one to two tenths at best with some downslope shadowing likely here
in the Champlain Valley associated with 850mb winds of 30 to 40
knots. Best chance of a coating of wet snow would be northern Greens
and NEK Tues eve. With clouds thickening rapidly on Tue expect high
temps mainly in the 30s after a chilly start.
Weak upper level disturbances in the fast westerly flow aloft and
some mid and high level clouds persist Wed and Wed night as a mild
surface flow continues from the south and southwest. 925mb temps
warm between 2-5 deg C by Wed...supporting highs well into the 40s
to around 50 with lows Wed night in the lower to mid 30s.
More snow melt looks likely based on winds and temps Wed with rises
on local streams and rivers.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 336 PM EST Sunday...The much above normal temp trend
continues late week into the weekend with developing eastern
CONUS mid/upper level ridging. Next main storm system still
looks like it will come Friday into Saturday with a primary low
pressure system tracking to our north and west of our region.
On Thu a weak short wave moves through the northern CWA with some
warm moist advection ahead of a weak cold front which passes from
north to south late in the day or Thu eve. Highest chances for
precipitation will be in the north and mainly in the form of light
rain showers. High temperatures again well into the 40s to around 50
with 925-mb temps of 3-7C north to south but cooling below 0C Thu
night into Friday a.m.
Rising 500mb heights forecast along with primary low pressure
tracking north and west of our region through the Great Lakes Friday
through Saturday. Models still showing the potential for a secondary
triple point low along the NE coast which means we never really get
too warm. Details continue a bit murky but it looks like we`ll be
affected first by a warm front later Fri/Fri night and cold occluded
front Sat before things quiet down on Sunday as the storm exits the
region. Still too early to determine any details of how much
precipitation and temperatures. Right now it appears that a mix of
precip may fall with the warm front on Friday followed by mainly
windy and mild with rain showers on Saturday, before changing back
to snow showers Sat night. Way too early to determine overall
threat and potential impacts.
.AVIATION /00Z Monday THROUGH Friday/...
Through 00Z Tuesday...Mainly BKN/OVC VFR cigs in the 035-060 AGL
range overnight with passage of weak cold front. A stray
sprinkle or flurry will be possible along frontal boundary in
the 00-04Z time frame. Exception at KSLK where occasional MVFR
in the 025 AGL range is expected overnight. Skies trend mainly
SKC at KMSS after 06Z, and other terminals in the 12-18Z time
frame. Winds generally west/northwesterly 5 to 10 knots
overnight, trending north/northwesterly after 12Z Monday.
Outlook 00Z Tuesday through Friday...
00Z Tuesday through 21Z Tuesday...VFR/high pressure.
21Z Tuesday through 03Z Wednesday...Mix of VFR/MVFR/IFR in
showers/light mixed precipitation with warm frontal passage.
03Z Wednesday onward...mainly VFR/high pressure. Will see a
warm front approaching from the SW later Friday with increasing
clouds and chances for MVFR rainfall per current indications
late in the day.