615
FXUS61 KBTV 180203
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1003 PM EDT Tue Jun 17 2025

.SYNOPSIS...
Heat will continue to increase through Thursday with daily chances
of afternoon thunderstorms and periods of moderate to heavy rain
showers. A cold front moving through the region on Thursday will
bring increased chances of stronger storms that could produce
damaging winds and downpours potentially leading to localized flash
flooding. Unsettled conditions will linger into the weekend before
high pressure builds over the eastern U.S. bringing the potential
for dangerous heat next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 956 PM EDT Tuesday...Have taken down the Lake Wind
Advisory with this evening update as wind gusts have dropped to
20 knots at Colchester Reef and 19 knots at Diamond Island as of
940 PM. Winds over the Lake will only gradually diminish through
the remainder of the night. As the pressure gradient decreases
through the day Wednesday, expect wind gusts to continue to
diminish Wednesday. Otherwise, remainder of the night will be
quiet with some increasing chances for showers over southern
counties towards Wednesday morning. Previous discussion
follows...

Cloudy conditions and scattered showers continue across the
region this afternoon into the evening, with somewhat dreary
conditions across southern Vermont. Lingering cloud cover and
showers will make for mild overnight temperatures, with lows
only dropping into the 60s. Another day of warming temperatures
and increasing humidity can be expected for Wednesday as an
upper level trough gradually approaches the region. High
temperatures look to warm into the low to mid 80s across the
region, with dewpoints in the mid to upper 60s making it quite
muggy. A few showers will be possible throughout the day on
Wednesday, with plenty of moisture and instability available,
although a lack of forcing and weak shear will help limit any
thunderstorm development. Any thunderstorms and showers that do
develop will likely feature periods of moderate to heavy
rainfall given abundant moisture, with PWAT values in excess of
an inch. Surface winds will also be light, which could lead to
slow-moving storms and enhance rainfall amounts. The warm and
humid conditions will continue overnight Wednesday, with
overnight lows only dropping into the 60s, with parts of the
Champlain Valley hardly dropping below 70.

&&

.SHORT TERM /THURSDAY NIGHT/...
As of 349 PM EDT Tuesday...Confidence in strong to severe
thunderstorms on Thursday continues to increase. A warm and humid
airmass will be in place; 925mb temperatures will approach 24-25C,
while PWATs surge to nearly 2 inches. Meanwhile, an upper trough and
associated cold front will sweep eastward through the Great Lakes,
eventually swinging through our area later Thursday into Thursday
night. There`s still some disparity between forecast models in
timing of these two latter features, and the best shear may lag
behind the front somewhat. However, still anticipate 35-45 kt of
0-6km shear. With CAPE values around 1500 J/kg (or perhaps higher if
one believes the NAM), the overall scenario still looks very optimal
for strong to severe thunderstorms. Stronger storms would be capable
of producing hail and gusty winds. In addition, given deep warm
cloudy layers and the high PWATs, heavy rainfall rates will be
possible, as well. Convection should have fairly good forward
motion, but some cell training is possible. Even without training,
rates in excess of 1 in/hr could result in localized amounts of 1-2
inches. So localized flash flooding will be possible as well,
especially if heavier rain occurs in areas similar to any Wednesday
storms. We remain in a Slight Risk of severe weather from SPC, and a
Marginal Risk of Enhanced Rainfall from the WPC, which both seem
appropriate. As Thursday draws closer, we`ll be within the realm of
the hi-res CAMs, so hopefully details will become more clear in the
next 24 hours or so.

In addition to fueling thunderstorms, the heat and humidity will
make for an uncomfortable day. Highs will range from around 80F in
the Adirondacks and St Lawrence Valley, to the mid and even upper
80s in the Champlain and lower CT Valleys. We did increase highs
just a tad with this forecast as some of the latest guidance shows
we could get some decent sunny breaks during the mid morning to
early afternoon, especially from the Champlain Valley eastward. Heat
index values will be somewhat marginally high, in the mid 80s to
near 90F, but could still lead to some increased risk of heat
illness in sensitive and vulnerable populations. South winds will be
gusty though, which may help keep those without A/C a little cooler.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 349 PM EDT Tuesday...The main concern for the extended period
continues to be the increasing confidence in dangerously hot and
humid conditions for early next week. However, before we get there,
we`ll have to contend with a potential decaying MCS/ridge roller
over the weekend. Read on for details.

Friday and Saturday...The upper trough will exit to the east while
ridging starts to build into the area. A shortwave may bring a few
showers and thunderstorms to mainly northern areas Friday, but the
bigger story will be the cooler temperatures, though still close to
normal. As ridging nudges into the area, long range guidance has
started to come into better agreement, showing a decaying MCS riding
down along the top of the ridge, moving from the Upper Midwest,
across the Great Lakes, and into the Northeast. Still plenty of
uncertainty with timing/placement, but have continued with 40-50%
PoPs for Saturday afternoon/night as models seem to be converging on
that time frame.

Next week...strong ridging will build over the region, ushering in
what will likely be the hottest airmass so far this season. NBM
probabilities for highs above 90F continue to be quite high,
particularly Monday and Tuesday, when much of VT and northern NY is
included in values of 50 percent or more. In fact, portions of the
central/southern Champlain Valley and lower CT Valley have
probabilities of 90F or more of more than 80%. While this may be a
bit overdone, it points toward a period of very warm temperatures.
Unfortunately, this will be accompanied by high humidity and
dewpoints well into the 60s or even above 70F. This means that the
overnights will give little relief as they`ll remain very muggy and
warm. Should this trend hold true, heat index values of 90-100F
would be likely, leading to increased risk of heat stress and heat
related illnesses, particularly in sensitive and vulnerable
populations. Please stay tuned, as trends should become more clear
as we approach early next week.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...Variable conditions currently across our
TAF sites with VFR at PBG and MSS to MVFR at BTV/SLK/EFK/RUT and
intervals of IFR at MPV. Sounding data shows strengthen low
level inversion with varying amounts of low level moisture
across our central and eastern TAF sites. Given the southeast
low level flow, feel the highest probability of developing IFR
cigs will be at MPV toward midnight, with intervals of IFR cigs
possible at RUT, but southeast flow might keep cigs just above
IFR conditions. Otherwise a mix of MVFR/VFR will prevail
overnight at PBG/SLK/BTV and EFK. Conditions will slowly improve
to VFR most sites with MVFR cigs lingering at EFK/MPV and RUT
until 16z or so on Weds. Southeast winds of 5 to 15 knots will
slowly become south/southwest by Weds.

Outlook...

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

&&

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

&&

$$
SYNOPSIS...Kremer
NEAR TERM...Duell/Kremer
SHORT TERM...Hastings
LONG TERM...Hastings
AVIATION...Taber