FXUS61 KBTV 210545
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
1245 AM EST Mon Jan 21 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 TONIGHT/...
As of 711 PM EST Sunday...The forecast remains in good shape as
of early evening. Other than tweaking sky cover to show some
occasional partial breaks in the overcast and to trend hourly
temps/dewpoints toward most recent observational data no changes
were made. Have a warm and safe evening.
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 SUNDAY/...
As of 307 PM EST Sunday...Staying active through the extended
period, and once again turning colder after a brief warm up.
Precipitation will spread over the region on Wednesday as warm
air advection sets up ahead of weak low pressure skirting up
just to our west. Temperatures will initially be cold enough
throughout the column for all snow, but warming will take place
on a 850mb 50kt jet, allowing a transition to a rain/snow mix
late Wednesday into Wednesday night. Wouldn`t be surprised to
see a little sleet during the transition, but this should be
short- lived. The weakening low moves to the north Wednesday
night, with cooler air moving in behind a frontal boundary on
Thursday. Uncertainty grows thereafter as another wave of low
pressure is progged to develop along the front sometime
Thursday, model differences in the low`s timing and track, which
would have implications for precip type and placement.
Regardless, the system looks to move off to the east Thursday
night. Model differences continue thereafter, but it looks like
cold conditions resume by the weekend as an upper trough swings
over New England.
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...Mix of VFR/MVFR will continue through the
overnight hours, with brief reductions in vsby to IFR in
light snow possible. Very light snow will remain persistent at
northern terminals through mid-day Monday then rapidly decrease
in coverage after 18Z with skies scattering to FEW-SCT VFR by
00Z. Winds will remain brisk out of the north/northwest from
8-12 kts overnight, and increase to 12-15kts after 12Z with
gusts 20-25 kts through the remainder of the period.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Slight chance SHSN.
Wednesday: Mainly VFR, with areas MVFR and IFR possible. Likely
Wednesday Night: Mainly MVFR, with areas IFR possible. Likely
SHSN, Likely SHRA.
Thursday: Mainly IFR, with areas MVFR possible. Likely SHSN,
Thursday Night: Mainly MVFR, with areas VFR possible. Chance
Friday: Mainly VFR, with local MVFR possible. Chance SHSN.
VT...Wind Chill Warning until 1 PM EST this afternoon for
Winter Weather Advisory until 7 AM EST this morning for
NY...Wind Chill Warning until 1 PM EST this afternoon for
Winter Weather Advisory until 7 AM EST this morning for NYZ028-