658 
FXUS61 KBTV 250822
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
422 AM EDT Wed Aug 25 2021

.SYNOPSIS...
Hot and humid conditions are on tap for the North Country today and 
Thursday with temperatures both days warming into the mid 80s to 
lower 90s. The next chance for precipitation will come Thursday 
afternoon as scattered thunderstorms will be possible ahead of an 
approaching cold front. This front will roll through late Thursday 
night into the first half of Friday with much cooler temperatures 
expected Friday and through the upcoming weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 421 AM EDT Wednesday...Another hot and humid day is on tap for
the North Country with the axis of the deep layer ridging moving
overhead today. Temperatures will likely be a degree or two warmer
today compared to Tuesday as less clouds during the morning hours
will yield warmer afternoon temperatures. Given the amount of dry
air in the mid-levels, as we warm into the mid 80s to lower 90s this
afternoon, we should mix to around 800 mb which will help bring some
of this drier air down to the surface. This will allow for dewpoints
to drop into the lower 60s this afternoon and keep heat indices
below 95 degrees across the entire region this afternoon. While the
daylight hours are expected to be mostly sunny, we will see
increasing cloud cover during the overnight hours as we advect
moisture into the region from the west and a couple of low amplitude
shortwaves move uneventfully across the North Country.

Thursday will be yet another hot and humid day with many sites once
again seeing temperatures in the mid 80s to lower 90s. This time,
however, we will see dewpoints in the upper 60s to lower 70s thanks
to the aforementioned moisture advection. With less dry air in the
mid-levels and less overall mixing expected on Thursday, we won't
see our dewpoints drop like they will this afternoon which will
create heat indices between 95 and 100 degrees across the Champlain
and Connecticut River Valleys. If conditions continue to look
favorable for these heat indices, a heat advisory will be issued in
a subsequent forecast package. There is one fly in the ointment,
however, as convection is possible across portions of the forecast
area Thursday afternoon ahead of an approaching cold front. Any
convection would obviously cool temperatures off and prevent some
areas from warming to their maximum potential. The thunderstorm
coverage should be rather isolated to scattered given a decent
amount of dry air in the mid-levels. The lack of surface convergence
will also yield a lack of areal coverage as thunderstorms will be
most likely over higher terrain given orographic lift. With 0-6 km
shear values near 20 knots, it's unlikely we see any organized
convection which could keep the convection focused over the higher
terrain and out of the valleys. Heavy rain would be the main concern
with the thunderstorms given PWATs between 1.75" and 2.0" with
severe convection unlikely given the lack of convergence and shear.
We could see some of these thunderstorms continue into the evening
hours but with the loss of heating and associated decrease in CAPE,
we should see convection dwindle quickly after sunset.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 421 AM EDT Wednesday...Afternoon/evening convection will wane
going into Thursday night with the loss of diurnal heating and the
pre-frontal trough exiting east of the region, but with the parent
cold front still to pass can't rule out a few stray showers.
Otherwise, a much welcomed cold front will be poised to drop through
the CWA on Friday with cool high pressure building in behind it from
the north. Surface dewpoints drop into the low 50s and highs will
range through the 70s under partly sunny skies...ahhhhhh. Tranquil
conditions continue into Friday night under partly cloudy skies with
lows widespread in the 50s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 421 AM EDT Wednesday...Little overall change for the extended
forecast heading into the weekend and early next week which offers
an unfortunate return of humidity, but not as oppressive as of late
and brief. As cool high pressure shifts east Saturday a building
ridge over the eastern Great Lakes will gradually move into the
Northeast with warm south/southwesterly flow returning. A warm
frontal passage will present the chance for showers Saturday
afternoon/night and additionally some thunderstorms Sunday in the
warm sector before another cold front passage on Monday. Humidity
will be comfortable Saturday with dewpoints in the 50s, but
mid/upper 60s and perhaps some 70s return for Sunday and Monday.
Cooler and drier conditions look to return Tuesday.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Through 06Z Thursday...We are looking at VFR conditions and 
light winds persisting through the forecast period. The only 
exception will be pockets of IFR to LIFR fog developing across 
KSLK and KMPV from 7Z to 13Z this morning.

Outlook...

Thursday: VFR. Chance SHRA, Chance TSRA.
Thursday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Friday: VFR. Slight chance SHRA.
Friday Night: VFR. Slight chance SHRA.
Saturday: VFR. Chance SHRA.
Saturday Night: Mainly VFR, with areas MVFR possible. Chance
SHRA.
Sunday: MVFR. Chance SHRA.

&&

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

&&

$$
SYNOPSIS...Clay
NEAR TERM...Clay
SHORT TERM...Lahiff
LONG TERM...Lahiff
AVIATION...Clay