FXUS61 KBTV 120804
Area Forecast Discussion
National Weather Service Burlington VT
404 AM EDT Wed May 12 2021
High pressure will slowly build into the region for late week,
resulting in less areal coverage of showers and warmer temperatures.
Still anticipating a few showers again today across central and
northern VT, with temperatures warming into the mid 50s to lower
60s. On Thursday, temperatures warm back into the 60s with a few
scattered showers possible in the late afternoon near the
International Border. Areas of patchy frost are anticipated tonight
across portions of the North Country.
.NEAR TERM /THROUGH THURSDAY/...
As of 402 AM EDT Wednesday...Well lets first start with the good
news, overnight summit webcams at Sugarbush and Stowe show snowfall
approaching 3 inches, with snow levels down to 2800 ft, a little
over 5 weeks until we make the turn. Water vapor shows s/w energy
and mid level ribbon of moisture responsible for the mix of
rain/snow shower activity acrs our fa is dropping south and
dissipating. Expect areal coverage to wane quickly this morning and
become mainly confined to the trrn, and have shown that in pops/qpf,
with little additional accumulation expected. Meanwhile, our next
weaker 5h vort and less favorable moisture is located over central
Canada attm and wl approach our northern VT fa by 18z. This combined
with some sfc heating and weak instability wl allow for scattered
aftn/evening showers to redevelop again today. However, best forcing
and dynamics should be acrs central/northern and eastern VT,
including the NEK, where chc pops wl be the highest. Once again,
soundings show very dry llvls with steep sfc to 3 km lapse rates
>7.5 C/km, supporting high based convective showers. Progged 925mb
temps are a degree or two warmer this aftn, supporting highs mid 50s
to lower 60s.
Meanwhile, tonight 1032mb sfc high pres near MKE wl slowly expand
eastward into our fa, resulting in clearing skies and lighter mainly
trrn driven winds overnight, which wl allow temps to cool quickly.
Expecting patch/areas of frost to develop and have posted frost
advisory acrs the SLV and parts of central/northern/eastern and
southern VT, where the growing season has official started. Upstream
obs acrs MI and southern Canada show even with some gradient
lingering, temps have fallen into the upper 20s to mid 30s and think
this wl be a similar scenario for portions of our cwa. Still some
concerns about lingering clouds in the northwest upslope flow
pattern, especially acrs the mtns of VT, which could hold temps in
the upper 30s. A mostly dry day is anticipated on Thurs with
northwest flow aloft prevailing. NAM/GFS do indicating 700 to 500mb
vort, along with enhanced 700mb moisture wl approach our fa by 21z
Thurs. This energy/moisture, combined with some weak sfc based cape
in the 100 to 300 j/kg wl help in the development of scattered
showers near the International Border, where I have placed 30 to 40%
pops. Progged 925mb temps near 10c, support highs back into the 60s
most locations on Thursday.
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 402 AM EDT Wednesday...A narrow band of precipitation along a
dewpoint boundary will shift southeast into Vermont and then
dissipate Thursday night. Overnight lows will settle in the mid 30s
to mid 40s. Relatively dry to start Friday. Forecasts have trended
warmer for Friday, with 925 hPa temperatures climbing towards
12-13C. This would indicate we reach the upper 60s to lower 70s. We
will be deeply mixed up to 650 hPa. Fortunately, winds aloft are
only 25 knots or so, but it could be a bit breezy. With the steep
lapse rates and sufficient moisture this instability should produce
convection during the day that steadily wanes after sunset.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 402 AM EDT Wednesday...Scattered afternoon showers remain the
theme of the extended, with temperatures in the mid 60s to lower
70s. An upper trough will be moving into the region on Saturday, but
atmospheric instability is only just enough to produce hit-or-miss
convection. Sunday continues to appear a bit more unstable as the
upper trough begins to shift east with about 500 J/kg of CAPE
available. Though mainly the result of tall, skinny profiles, the
deeper updrafts could be enough to generate some thunder, and have
mentioned a slight chance focused on where CAPE is highest.
Heading into the new week, guidance has begun to shift and more
apparent signals are starting to emerge. Another upper trough will
propagate towards the region on Monday with some additional shower
activity possible. As we head towards Tuesday and Wednesday, a
negatively tilted upper ridge will develop with a pocket of
vorticity carving out New England. A cold front will attempt to
descend across the region, but will likely washout. This would
result in a drier period of weather for us, and we could be looking
at an end to the scattered showers for a time. Still, given this is
a relatively new trend, have still depicted at least a slight chance
of precipitation on Tuesday and Wednesday. Temperatures remain
seasonable with mid 60s to lower 70s.
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
Through 06Z Thursday...Occasional rain showers continue thru 08z
at mpv/slk/btv and rut with mvfr cigs. Expecting ifr cigs at slk
to prevail thru 10-11z and develop at mpv by 08z and lift by
11z. The combination of upslope flow and increase moisture from
precip wl produce these ifr cigs. Otherwise, conditions wl
improve to vfr btwn 12-15z at all sites with some widely
scattered showers redeveloping by late morning. Winds are
northwest 4 to 8 knots overnight and continue into Weds with
some localized gusts 15 to 18 knots possible.
Thursday: VFR. Slight chance SHRA, Slight chance TSRA.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Slight chance SHRA, Slight chance TSRA.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. Chance SHRA, Slight chance TSRA.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. Chance SHRA, Slight chance TSRA.
VT...Frost Advisory from 2 AM to 8 AM EDT Thursday for VTZ006-
NY...Frost Advisory from 2 AM to 8 AM EDT Thursday for NYZ026-027-