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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 290558
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1258 AM EST Sat Feb 29 2020

.SYNOPSIS...
Aside from a few mountain snow showers, a few cool, dry days
are in store for the weekend. Several chances for light
precipitation exists next week along with a warming trend taking
temperatures into the upper thirties to lower forties for day
time max temperatures.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 1252 AM EST Saturday...Lake effect snow band has drifted
south and only light snow showers are anticipated through the
overnight. Have cancelled our hazards with this update. Previous
discussion follows.

As with the previous evening update, the primary issue was
accounting for the latest radar trends. The lake-effect snow
band has intensified somewhat as it accelerates southeastward,
currently just south of a line from Saranac Lake, NY to
Plattsburgh, VT to Enosburg, VT. An updated special weather
statement has been put out at this hour to caution motorists for
rapidly changing conditions tonight in association with this
heavy snow, as visibility drops below a half-mile in this band.
Also noticed on webcams snow persisting in places such as
Springfield and St. Johnsbury in Vermont, so bumped up
precipitation chances there in the near term. Otherwise, just
minor tweaks made to winds and temperatures with going forecast
looking good.

Previous discussion...Lake effect warning for southeastern St.
Lawrence and Winter Weather Advisories have been extended to 5 AM.
Additionally, southwestern St. Lawrence has been added, as 3"-6"
accumulations are expected with locally up to 7" towards areas like
Gouverneur, Edwards, and Fowler. Based on reports of observed 5"-8"
of snow observed over northern Vermont, have updated to forecast
snow totals provide an additional 2" to 5". Thus, Winter Weather
Advisories have also been published for northern Vermont covering
Franklin County eastward to the Northeast Kingdom through 1 AM.
Outside of the warning area, additional accumulations of a dusting
to 2" are expected.

Visible satellite is quite gorgeous today. One can see the curl of
mid to upper clouds influenced by the closed upper low just north of
the International Border. The individual cells of lake effect snow
showers embedded within lengthy lake effect snow bands are also
visible in stunning detail on satellite imagery. Cannot reiterate
enough how wonderful GOES-16 is. A subtle near surface boundary is
lifting northward in a line from southern St. Lawrence through
Chittenden and up to the Northeast Kingdom of Vermont. Lake effect
has been streaming parallel to this boundary and to the north. As
this lifts northward, expect the lake effect snow showers to push
northward towards the International Border. Gustier winds lie south
of the boundary, where there are even pockets of sunlight at times.
Overall, not seeing much blowing snow. Forecast shows less blowing
snow potential over the coming hours, and think this is reasonable.
With the higher solar angle and with temperatures near enough to the
melting point, think enough melting and compaction is taking place
to mitigate this factor. A bit further south is lake effect snow
streaming all the way from Lake Erie, though snowfall reports are a
bit more sporadic out of this band based on surface observations.
After sunset, a strong shortwave currently digging across Michigan
will quickly eject eastward, and will push the lake effect band back
to the south later tonight into the overnight hours. Lake effect
snow should cease by dawn Saturday.

With the upper low meandering in place on Saturday and with adequate
low-level moisture and modest lapse rates in place, anticipate
upslope snow showers to linger over the higher summits. Summit snow
showers could briefly retreat westward downhill with mostly diurnal
fluctuations impacting stability and as wind speeds decrease behind
the mid-level front, but accumulations will be marginal at best.
Pressure gradients will remain a bit constricted, so there should at
least be some winds still out of the northwest. Source air mass is
pretty chilly, so a few below average days are on tap. Lows tonight
will be in the upper single digits to mid teens. Highs on Saturday
will hover around the upper teens to lower 20s, and then the
overnight lows on Saturday into Sunday morning will settle into the
single digits above zero for most areas.

&&

.SHORT TERM /SUNDAY NIGHT/...
As of 340 PM EST Friday...Quiet period of weather Sunday as upper
level ridging begins to build in. NW flow aloft will keep lingering
clouds across the high terrain through the morning hours, but
eventually drier air should work its way south and bring about
mostly sunny skies. Should be a relatively nice day with below
normal temperatures in the mid 20s with near normal temperatures
Sunday night in the mid teens. Non-diurnal temperatures on
Sunday night will see lows early in the night as high pressure
crests overhead. Our next approaching system approaches from the
west with increasing southwesterly winds Sunday night and like
precipitation Monday morning.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 340 PM EST Friday...Relatively active period of weather for the
first part of the long term with the potential for very light mixed
precipitation Monday morning. Have only run with rain/snow surface T
as degree of warm nose is questionable and precipitation amounts are
very light (only a few hundreths). Soundings indicate the potential
for some light sleet but given degree of warm nose is incredibly
slight and model variability have kept things simple at this time.
Temperatures warm to spring readings in the low to mid 40s Monday
through Thursday. A weak clipper will track across bring with it a
chance for rain Tuesday night. Again precipitation remains quite
light with QPF amounts less than 0.10". After this, quite a large
degree of uncertainty for timing and evolution of next storm with
CMC/ICON/ECMWF showing high pressure building south out of Canada
with moisture streaming from the Gulf of Mexico staying suppressed to
our south. Currently, GFS is outlier with highly amplified large
scale pattern over eastern CONUS and potential for either heavy rain
or a quick shot of snow for Wednesday. Have offered generally 40-50%
PoPs for mid week to handle this variability. Will dial in this
forecast (for more snow, finger crossed) over the weekend.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...Lake effect snow band across our area is
drifting south and diminishing a bit. May still have some light
mountain snow showers overnight, mainly covered this with VCSH.
Some lingering MVFR ceilings, but conditions generally improving
through the 24 hour TAF forecast period.

Outlook...

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

&&

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

&&

$$
SYNOPSIS...Haynes
NEAR TERM...Haynes/Kutikoff/Neiles
SHORT TERM...LaRocca
LONG TERM...LaRocca
AVIATION...Neiles