FXUS61 KBTV 011124
Area Forecast Discussion
National Weather Service Burlington VT
624 AM EST Mon Mar 1 2021
Active and very changeable weather conditions expected across the
North Country today into tonight. A series of cold fronts will
produce scattered rain changing to snow showers with embedded snow
squalls this afternoon and evening. Behind these boundaries gusty
northwest winds develop with sharply falling temperatures. These
localized gusty winds may cause a few power outages, while wind
chill values drop to near 20 degrees below zero by Tuesday morning.
.NEAR TERM /THROUGH TUESDAY/...
As of 615 AM EST Monday...First boundary is moving acrs the SLV
and into the dacks with a broken line of mainly rain showers.
Expect this to enter the cpv shortly and exit VT by 16z.
Analysis shows dry slot with some breaks possible midday, before
arctic boundary arrives btwn 18z-00z with more snow showers and
potential embedded snow squalls. Still some uncertainty on
evolution of snow squalls, given limited llvl convergence, but
instability and dynamics look pretty favorable on the latest 06z
data. So have continued with chc/likely pops for snow showers,
with embedded stronger convective elements capable of producing
isolated snow squalls. Would not be surprised if several snow
squall warnings are issued this aftn/evening acrs our fa.
Otherwise, enjoy the relatively warm temps now, as the tumble
begins this aftn and continues overnight with developing gusty
winds and bitterly cold wind chill values. Welcome to the first
day of meteorological spring across the North Country.
Previous discussion below:
A very active 12 to 24 hours in the weather department with
rapidly changing conditions expected as a series of cold fronts
swing acrs our cwa. A 30 to 40 degree drop in temps are expected
by this time on Tues acrs our cwa, and when you have large temp
swings its associated with very gusty winds and potential snow
showers and embedded snow squalls.
Wind advisory in effect for eastern Dacks into most of
central/eastern VT, including Northeast Kingdom from 18z today thru
18z Tues for localized gusts 50 to 55 mph and potential power
Wind chill advisory in effect for northern Dacks and most of
central/eastern VT from 03z tonight until 16z on Tues for wind chill
temps between 20 and 30 degrees below zero.
Special weather statement for potential snow showers and embedded
snow squalls this aftn/evening during commute, along with
highlighting potential flash freeze.
Surface analysis places first cold front approaching the SLV attm
with broken line of showers and wind shift to the west. Meanwhile,
water vapors showing good deep layer moisture ahead of this
boundary, with sharp dry slot over central Great Lakes, which may
produce a few breaks in the overcast around lunchtime today. This wl
help to destabilize us this aftn, as secondary arctic boundary
located over the northern Great Lakes and associated pocket of
enhanced mid lvl moisture swings acrs our fa to produce snow showers
with a few embedded snow squalls.
Parameters have become slightly more favorable for stronger
convective elements this aftn, with better pockets of instability
(sfc based cape of 50 to 150 j/kg), axis of enhanced mid lvl
moisture (confined on water vapor), and slightly better llvl
convergence and associated 925mb fgen forcing. Similar to summer-
time convection, the uncertainty is amount of instability,
evolution/placement and how robust updrafts become to produce
embedded snow squalls. Given high resolution data, including the 06z
HRRR, 00z NAM 3km/RGEM and local BTV 4km all support the idea of
scattered snow showers developing aft 18z, with embedded snow
squalls possible, per locally developed snow squall parameter
showing values in the 4 to 6 range. Any snow squalls wl have
potential to produce a quick inch or two of snow, along with sharply
falling sfc vis below 1/4sm. This combined with road temps above
freezing and some melting snow pack lately, feel the potential for a
flash freeze is likely in spots, making for localized difficult
travel, especially the evening commute. Total snowfall generally a
dusting to 3 inches in the most persistent snow shower activity and
good luck measuring with the gusty winds.
Next item wl be very strong/gusty winds along and behind boundary
this evening into early Tues morning. Guidance continues to show
850mb winds of 50 to 60 knots, especially central/eastern VT, while
supporting very good mixing with steep lapse rates under strong llvl
caa. This occurs with 6 hr pres rise couplet of 10 to 12mb and
developing gradient from progged sub 970mb low pres eastern Canada
and building 1032mb high over Ohio Valley. With developing thermal
inversion just below mtn summits, expect enhanced downslope flow on
eastern side of the Greens and dacks, where localized gusts up to 55
mph is likely tonight into Tues morning. Similar type wind gusts are
likely acrs the exposed trrn of the NEK too. Elsewhere, gusty
northwest winds of 30 to 40 mph are likely overnight into Tuesday.
Isolated to scattered power outages are possible, given wind gust
Enjoy the very warm temps in the mid 30s to lower 40s this morning,
as caa develops and temps plummet late this aftn into the overnight
hours. First cold front will drop 850mb temps in the -2C to -5C by
18z, while 925mb values range from 1C to -3C, supporting snow levels
dropping from summits to 1500 ft. Meanwhile, secondary surge
develops btwn 21z-00z this evening and 925mb temps drop btwn -10c
and -15C by 00z and close to -20C by 06z tonight, under strong llvl
caa on blustery northwest winds. These sharply falling temps this
evening will cause any leftover standing water from snow melt and
precip earlier in the day, to quickly freeze, creating the potential
for a flash freeze. These are always very challenging to predict, as
uncertainty remains with how much precip falls and how quickly sfc
conditions dry with gusty northwest winds, but potential exists.
Temps drop btwn -5F and 5F by Tues morning with wind chill values in
the -15 to -30 range. Highs on Tues warm into the single digits to
near 20F warmest valleys with increasing amounts of sunshine and
lighter winds by afternoon.
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
As of 312 AM EST Monday...A weakening clipper system will move
through the area Wednesday morning, with little impact other
than a few light morning snow showers and a transition to some
breezy northwest winds during the afternoon. Lows Wednesday
morning will be in the teens for most locations, except the
single digits in typical colder locations of the Northeast
Kingdom and the northern Adirondacks. Southerly/southwesterly
low-level flow ahead of the system will support one of the last
days with highs above freezing that we`ll see in a while. Look
for mild temperatures topping out in the mid to upper 30s.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 312 AM EST Monday...Another arctic front will push down from
Canada Thursday morning, marking a transition back to seasonably
cold conditions. The region will remain under northerly/northwesterly
flow through at least Saturday, which will favor a prolonged period
with highs in the teens to 20s and lows in the single digits to low
teens. In the upper levels, an upper low will remain quasi-stationary
over eastern Canada, blocked from moving out to sea by strong high
pressure developing over Greenland. This will allow the upper-
low to stall for some time to our northeast, perhaps even retrograding
westward some, and will result in continued cold air advection and
numerous shortwaves rippling through New England for the end of the
week. While no significant precipitation is expected, can`t rule
out some scattered light snow showers between Thursday and Saturday
as these shortwaves move through.
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
Through 12Z Tuesday...Very changeable flight categories
anticipated over the next 12 to 24 hours acrs our taf sites.
As a sfc cold front moves acrs our taf sites scattered rain
showers are expected btwn 12z-15z this morning, with additional
periods of ifr vis/cigs possible in the heavier showers. Winds
shift to the west and become gusty again after 15z at 15 to 25
knots and cigs should improve especially PBG/MSS and BTV to
mvfr/vfr. A secondary arctic boundary arrives aft 20z with
additional snow showers and embedded snow squall possible,
especially SLK/MPV/BTV and Rut. A sharp drop in vis below 1/2sm
is possible with brief moderate to heavy snow and gusty
northwest. Areal coverage of snow showers become trrn focused
aft 03z, as strong northwest winds of 15 to 25 knots with gusts
up to 35 knots develop at most taf sites overnight, along with
Tuesday: VFR. Windy with gusts to 35 kt. NO SIG WX.
Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHSN.
Wednesday: MVFR. Slight chance SHSN.
Wednesday Night: Mainly VFR, with areas MVFR possible. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. Slight chance SHSN.
Friday: VFR. Slight chance SHSN.
VT...Wind Chill Advisory from 10 PM this evening to 11 AM EST
Tuesday for VTZ003-004-006>008-010-016>019.
Wind Advisory from 1 PM this afternoon to 1 PM EST Tuesday for
NY...Wind Chill Advisory from 10 PM this evening to 11 AM EST
Tuesday for NYZ029>031-034.
Wind Advisory from 1 PM this afternoon to 1 PM EST Tuesday for