836
FXUS61 KBTV 151420
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1020 AM EDT Thu Aug 15 2024

.SYNOPSIS...
Expect a mixture of hazy skies and isolated to scattered
thunderstorms today. Some thunderstorms may produce gusty winds
and small hail. Warm and humid conditions through tomorrow will
give way to cooler and wetter weather from Saturday through
Monday.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 1009 AM EDT Thursday...Forecast remains in good shape this
morning, with only a few minor adjustments needed to
temperatures and winds. Skies continue to look quite milky outside
and on visible satellite this morning. Radar across the region
is currently quiet, although some ongoing showers and
thunderstorms continue across Maine into New Hampshire.

Previous Discussion...
Isolated clusters of showers and thunderstorms overnight have
been moving from north to south and have produced observed wind
gusts to 25 MPH. Expect a more amped up version of this activity
during the day today as the overall upper level pattern remains
stuck. The latest SPC outlook has placed most of our region in
a level 1 risk for severe thunderstorms, with wind and hail as
possible hazards during the afternoon and evening hours. Deep
layer shear will be on the low side near 20-25 knots, but
sufficient for organized storms particularly in eastern Vermont.
Think while the best overlap of CAPE and shear will be to our
east, our area can overachieve on moderately high CAPE days and
we we will have a surface trigger. A westward moving trough axis
will be near or over eastern Vermont this afternoon and become
the focus for somewhat more organized, multi-cellular
thunderstorms, aided by daytime heating. HREF mean surface-
based CAPE looks to be a regional maximum across northern
Vermont and New York this afternoon, most likely in the
1000-1500 J/kg range but with 20-40% chance of exceeding 2000
J/kg for much of the area. Noting that 500 millibar heights will
be rising gradually, progged instability will peak in the early
afternoon and then gradually diminish. That being said, strong
heating will steepen low level lapse rates, with mixing depths
upwards of 8,000 feet, which should help keep thunderstorms that
develop going even with the trend towards decreasing CAPE. As
in recent days, precipitable water and atmospheric relative
humidity will be moderate such that excessive rainfall is a low
concern.

The other topic of note is haze due to wildfire smoke. The prominent
northerly flow aloft is expected to bring an increase in
concentration of smoke today. Skies may become rather hazy and
air quality could be impacted based on the HRRR- and RAP-smoke
models, which show near-surface concentrations increasing later
today. Air quality forecasts and guidance can be found from the
NY State Department of Environmental Conservation and Vermont
Agency of Natural Resources.

Diurnally driven thunderstorms will be possible again tomorrow,
although it will be a quality with a lesser risk of impacts
given warming mid level temperatures, which will limit
thunderstorms to only the most vigorous updrafts and mainly over
the high terrain. Temperatures continue to trend a bit warmer,
with highs ranging through the 80s. With continued humid, but
not muggy, dew points, heat risk will be relatively low.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
As of 400 AM EDT Thursday...Friday night will be dry for the most
part, but there will be increasing chances for showers in our
western zones across Northern New York headed into Saturday morning
associated with an approaching warm front lifting towards the area.
Overnight low temperatures will be mild for mid August with lows
ranging through the 60s. Chance for showers will spread further into
the region on Saturday as low pressure over the Great Lakes slowly
tracks eastward, and associated warm front lifts into Northern New
York. This low will be very slow moving, therefore best chance for
showers and thunderstorms will be over Northern New York from Friday
night into Saturday. High temperatures on Saturday will range from
the upper 70s to lower 80s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 400 AM EDT Thursday...Vertically stacked surface and upper
level low pressure systems will be centered over the Great Lakes
region on Saturday night, and will only very slowly track eastward.
From Saturday night through Sunday there will be some scattered
showers around as shortwave energy rotates around very slow moving
upper low. On Sunday night into Monday these features will finally
pass east of our forecast area. Models continue to indicate humid
conditions in place through the weekend as we remain in warm sector
ahead of this low pressure system. At times precipitable water
values will surpass 1.50 inches, topping out around 1.75 inches.
This will mean there`s a chance for heavy rain until the boundary
finally passes on Monday. Our forecast area remains in Marginal risk
for excessive rainfall from Saturday right through Monday. Overall
rain threat looks highest in NY Saturday and Sunday as the upper
trough draws near, but then expands into VT Monday/Monday night as
the trough moves eastward, with a cold front eventually moving
through sometime in the early to mid week. Daytime temperatures
aren`t expected to be especially warm during this time frame with
highs only in the mid 70s to around 80, but it will be muggy, and
lows will remain in the 60s for most spots until a frontal passage
Monday or Tuesday. From Tuesday through Thursday there will be a
return to drier weather with high pressure ridging over the area.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Through 12Z Friday...Due to increasing concentration of wildfire
smoke, it looks like some MVFR visibilities associated with haze will
become probable today at most TAF sites. Currently seeing
several observations of 6 or 7 SM. In addition to haze, still
expect isolated showers and thunderstorms during the afternoon,
especially from the Champlain Valley eastward. Greatest chances
are between 18Z and 22Z. Light southwesterly winds through about
15Z will trend northwesterly thereafter between 4 and 8 knots,
and diminishing again towards 00Z. climatologically favored valleys, although 10
to 20 knots of westerly wind at the top of the nocturnal
inversion is present. While these winds are expected to relax
somewhat, this scenario will limit duration of fog. Another
round of fog from 06Z to 12Z is expected at SLK, possibly at
MPV where fog did not materialize early this morning, and
potentially at any site that sees rainfall late this
afternoon/evening.



Outlook...

Friday: VFR. NO SIG WX.
Friday Night: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Saturday: VFR. Chance SHRA, Slight chance TSRA.
Saturday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, Slight chance TSRA.
Sunday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight
chance TSRA.
Sunday Night: Mainly MVFR, with areas IFR possible. Likely SHRA,
Slight chance TSRA.
Monday: Mainly IFR, with areas MVFR possible. Likely SHRA, Slight
chance TSRA.

&&

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

&&

$$
SYNOPSIS...Kutikoff
NEAR TERM...Kremer/Kutikoff
SHORT TERM...Neiles
LONG TERM...Neiles
AVIATION...Kutikoff