FXUS61 KBTV 201959
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
259 PM EST Sun Jan 20 2019
Strong low pressure will depart across the Gulf of Maine and
into the Canadian Maritimes this evening and overnight. Will see
periods of lingering light snow across the North Country
tonight and into Monday, with additional light accumulations
expected. Also, strengthening north and northwest winds will
result in continued areas of blowing snow, with areas of reduced
visibility and slow travel conditions. With arctic air in place
over the next 24 to 48 hours, dangerously cold wind chills can
be expected areawide, with wind chill values falling to 25 to 40
below tonight through Monday. Fair and dry conditions are
expected on Tuesday, with highs in the teens and lighter winds.
Developing south winds and an approaching upper level disturbance
from the Great Lakes brings our next chance for precipitation on
.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 234 PM EST Sunday...Our major snowstorm is beginning to
wind down this afternoon. The best snowfall rates are departing
east of Vermont this afternoon, as 988mb sfc low shifts ewd
across Cape Cod and into the Gulf of Maine this evening, with
best large-scale forcing and deeper saturated layer exiting
eastward. With lingering low clouds and orographically blocked
flow (Froude #s expected below 0.5 next 24hrs), we can expect
continued periods of light snow across the Champlain Valley into
the mtns of central and nrn VT, which will likely linger into
the day on Monday. Additional accumulations generally expected
in the 1-3" range as we lose better dendrite growth. In addition
to the periods of lighter snowfall, NW winds of 15-25 mph with
gusts as high as 30-35 mph in the Champlain Valley, will cause
considerable blowing and drifting snow tonight into Monday
morning. With these concerns, decided to convert the expiring
Winter Storm Warning to a Winter Weather Advisory through 7 AM
Monday from the Champlain Valley eastward. Snow showers will be
somewhat less likely across nrn NY with drier air mass moving
in from sern Ontario.
Other major concern are the dangerously cold wind chills. Arctic
air filters back into the region on strengthening N-NW winds
this evening, and will see wind chills drop to 20 to 40 below
tonight thru Monday. Kept the Wind Chill Warning going through
1PM Monday...and may ultimately need to extend that a bit later
in time. Lows tonight generally -5F to -15F, with highs on
Monday only -5F to +5F. Diminishing winds and partial clearing
set up a better radiational cooling night for Monday night, with
1039mb sfc anticyclone building in across NY state late. Should
see temperatures drop rapidly late with the fresh snow pack and
some clearing. Lows Monday night expected between -8F at BTV and
generally -10F to -20F elsewhere. Locally down to -23F or colder
Please see our Local Storm Reports and Public Information
Statements for observed snow totals across the region as we
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 234 PM EST Sunday...Quieter wx expected Tuesday into
Tuesday night. Ridging sfc and aloft crests over NY and New
England on Tuesday with mostly sunny skies. Low-level air mass
remains cold, and will see highs only in the low to mid teens
areawide. Tuesday night, will begin to see some southerly return
flow as high departs to our east. In fact, wind gusts to 20-30
mph will develop in the Champlain Valley with strengthening
p-gradient toward daybreak Wednesday. Should see temps falling
early, then steady or slowly rising, especially from the
Champlain Valley wwd. Tuesday night lows generally 5 to 15F, but
locally near 0F in the more sheltered locations of the Northeast
Kingdom. May see some mid-level clouds advancing in after
midnight, and included 20-30 PoPs for -SW across far wrn zones
toward daybreak Wednesday.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 307 AM EST Sunday...The combination of waa lift/moisture will
produce a period of mainly snow showers on Weds morning.
Initially thermal profiles support all snow with 925mb to 850mb
temps <0c thru 18z, before 925mb temps warm above 0c across the
slv/western dacks. Thinking as temps warm enough to support a
mix, best lift/moisture will be exiting our cwa, with just some
lingering light rain/snow showers possible. In addition, gusty
850mb southwest winds of 40 to 50 knots will create some
shadowing across the cpv on Weds, which will limit qpf/snowfall.
A general 1 to 3 inches likely with localized 4 inch amounts
for high peaks and northern Greens. Temps warming mainly 20s
east of the greens to mid 30s.
Uncertainty develops associated with potential wave along the
boundary on Weds Night into Thurs. In addition, plenty of
uncertainty with regards to low level thermal profiles and
associated ptype. Have kept things simple for now with high chc/low
likely pops and rain or snow showers. System sweeps off the east
coast overnight Thursday with much cooler air arriving for Friday
into the weekend. Some lingering mountain snow showers are possible
with temps falling back to below normal values.
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
Through 18Z Monday...IFR/LIFR conditions will continue through
much of the period as a winter storm affects the area with
widespread moderate to locally heavy snow. The heaviest snow
with visibility 1/2sm or less will affect the terminals through
about 20z this afternoon, but overall anticipate snow to wane in
intensity through the evening hours as the storm pulls away.
However, winds have intensified in most spots and gusts to
22kt will be possible the remainder of the period. These winds
will keep visibility in the IFR category due to BLSN at most
terminals. Ceilings AOB 1500 ft will continue through the
period, though KRUT may pop up to 2500 ft after 02z tonight.
The heaviest snow
with vsby 1/2SM or less will affect terminals in the through
about 16Z with some sleet possibly mixing in at KRUT. Snow
lightens in intensity beyond 16-18Z as storm starts to pull away
but northerly winds gusting >20kts will keep vsby IFR or below
at many sites in BLSN through the remainder of the period.
Exception on winds will be KRUT where east-southeasterlies will
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Chance SHSN.
Wednesday: Mainly VFR, with areas MVFR and IFR possible. Definite
SHSN, Likely SHRA.
Wednesday Night: MVFR/IFR conditions possible. Likely SHSN,
Thursday: Chance SHSN, Likely SHRA.
Thursday Night: Chance SHSN.
Friday: Chance SHSN.
VT...Wind Chill Warning from 6 PM this evening to 1 PM EST Monday
Winter Weather Advisory until 7 AM EST Monday for VTZ001>012-
NY...Wind Chill Warning from 6 PM this evening to 1 PM EST Monday
Winter Weather Advisory until 7 AM EST Monday for NYZ028-035.