745
FXUS61 KBTV 012105
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
505 PM EDT Wed Jul 1 2026
.WHAT HAS CHANGED...
As of 505 PM EDT Wednesday...
A Severe Thunderstorm Watch has been issued until 11 PM for all
of northern New York and the Champlain Valley or New York and
Vermont. Damaging winds, frequent lightning, heavy rain, and
hail.
&&
.KEY MESSAGES...
As of 228 PM EDT Wednesday...
1. Major to localized extreme heat risk is expected through
Friday with widespread heat index values of 95F to 105F. Some
locations could exceed 105F heat index due to very warm air
temperatures and dewpoints rising into the 70s.
2. Daily chances for showers and thunderstorms will continue
through Friday. Some of these could be strong to severe, but there
remains considerable uncertainty in areal coverage and timing.
3. Hot and humid conditions will linger through the end of the
weekend with daily chances of showers and thunderstorms into next
week.
&&
.DISCUSSION...
As of 228 PM EDT Wednesday...
KEY MESSAGE 1: Dangerous heat will continue to impact Vermont
and northern New York today through Friday. Widespread
temperatures in the upper 80s to mid 90s have already been
observed with heat indices in the Champlain Valley already near
100F and near 105F in the St. Lawrence Valley. While just a
Heat Advisory is in effect for the St. Lawrence Valley with heat
indices near or at 105F in Potsdam and Ogdensburg from
localized urban heat island processes, increasing clouds from
thunderstorms in Ontario will help to limit the potential for
any extended Extreme Heat Warning conditions. The high heat
index values will be present both tomorrow and Friday afternoon
areawide, with the highest occurring Thursday with just about
everyone hitting 90F, and some locations could approach 100F.
Unfortunately, humidity will also be on the increase; dewpoints
will be in the upper 60s to low 70s. This will not only make for
dangerous heat index values exceeding 100F in places, it will
keep the overnights very warm and muggy, limiting any relief
from the hot and humid daytime hours. We`ll see a bit of a
respite from the humidity Friday and Saturday, but it will still
be very warm and muggy. Temperatures on the 4th will be around
the low to mid 80s, with some locations in the upper 80s in the
northern Champlain Valley and lower Connecticut Upper Valley.
Heat Index values for holiday activities will be around the mid
to upper 80s.
Heat related impacts will increase through the week due to the
cumulative effects from the prolonged heat wave. Please make sure to
take proper heat safety precautions, including limiting your time
outdoors, drinking plenty of water, and seeking indoor shelter with
air conditioning. Check on your relatives and neighbors, especially
if they are elderly. And don`t forget about your pets; bring them
indoors or provide them with ample shade and fresh cool water.
KEY MESSAGE 2: Heat and humidity will combine to create impressive SB
CAPE values today between 2500-4000 J/kg today and 1500-2500 J/kg on
Thursday, with some indications of values exceeding 3000 J/kg at
times. Shear will be less impressive, generally 25-35 kt depending
on the model and day, perhaps increasing to 40+ kt by Thursday
afternoon. We are currently monitoring a decaying MCS complex near
Montreal, which if it survives will move into a more favorable
environment as it approaches Vermont. Current track brings it into
the northern Champlain Valley around 3 PM with perhaps some gusty
winds, heavy rain, and frequent lightning. This threat will be
conditional on whether it survive and can tap into the better
environment. Otherwise today, with no strong forcing mechanism other
than the abundant instability, expect terrain-induced convection
today, generally remaining isolated to scattered in coverage. Strong
to severe thunderstorms can`t be ruled out given the large CAPE
values; SPC continues to encompass our entire forecast area in a
Slight Risk (level 2 out of 5) for Today. Model guidance during this
Ring of Fire setup has been lackluster at best. Convection across
Wisconsin and the upper mitt of Michigan will likely persist towards
eastern Ontario close to sunset, based on persistence and upper flow
patterns, which may pose an additional more organized thunderstorm
threat into this evening for northern New York, though confidence is
low at this time. Furthermore, additional thunderstorm chances may
exist into late tonight into the Champlain Valley and Vermont,
though any storms overnight are not expected to be severe. As one
would expect with the amount of humidity, we`re also in WPC`s
Marginal Risk (level 1 out of 4) for excessive rainfall. Any storms
that pop up today would at the least produce heavy rainfall, though
widespread flooding is not anticipated.
Additional thunderstorms are possible Thursday and Friday, though
marginal mid-level lapse rates due to loss of the EML will limit
instability and likely areal coverage/intensity for any convection
on Friday. We are included in a Marginal Risk (level 1 out of 5) in
SPC`s Day 2 severe outlook. Friday is more uncertain, both in areal
coverage and potential storm severity. Still, given the upcoming
holiday festivities, we urge everyone to stay tuned to later
forecast updates as strong/severe thunderstorms can`t be totally
ruled out any one day.
KEY MESSAGE 3: A stationary frontal boundary will be draped over
northern New York and Vermont Saturday night, drifting southwards
through Sunday night as the weekend comes to a close. This indicates
lingering chances for showers and thunderstorms, about 25-55%
chance, highest on Monday as a shortwave moves through the region.
Because of this, nights will be mild in the 60s with highs and
apparent temps remaining warm and muggy in the upper 70s and 80s.
Although it looks like it won`t be quite as hot as we`re expecting
these next couple of days, it is important to remember to drink
water and take frequent breaks if working outside, especially with
such an extended period of warmer weather. Next week, deterministic
model guidance diverges sharply, increasing uncertainty for the long
range forecast. At this time, high temperatures are most likely to
range in the 80s and lower 90s with chances for showers and
thunderstorms each afternoon through midweek.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Through 18Z Thursday...Daily chances for showers and thunderstorms
will continue through Friday. Some of these could be strong to
severe, but there remains considerable uncertainty in areal coverage
and timing. This afternoon, VFR conditions prevail across all
terminals, though this would likely change if a shower or
thunderstorm develops or moves over a terminal. At the moment,
chances of thunderstorms are around 20-40% for much of the next
several hours. Winds are out of the south-southwest at 5-15 knots
this afternoon and are expected to increase into the evening with
gusts 20-25 knots possible, most likely at MSS with southwesterly
channeled flow. After 00Z Thursday, precipitation is more likely to
become primarily showers instead of thunderstorms, though some
lightning could still persist into the evening and early overnight
hours. Brief low level wind shear may also impact a few sites
00Z-06Z Thursday as surface winds decrease while winds aloft remain
elevated. After 06Z Thursday, precipitation is much less likely, and
attention turns to favored fog locations like SLK and MPV,
especially if these sites receive rainfall this afternoon or
evening. Patchy fog is not out of the question at any site as
surface winds quickly decrease, but SLK and MPV look most favorable
for this. Any location that sees fog tonight will likely return to
VFR conditions around 12Z-14Z Thursday as fog burns off with the
rising sun. Additional thunderstorms are possible Thursday and
Friday, though areal coverage and intensity will likely be limited.
Outlook...
Thursday Night: VFR. Chance SHRA, Chance TSRA.
Friday: VFR. Slight chance SHRA.
Friday Night: VFR. NO SIG WX.
Independence Day: VFR. Chance SHRA, Chance TSRA.
Saturday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Sunday: VFR. Slight chance SHRA, Slight chance TSRA.
Sunday Night: VFR. Chance SHRA.
Monday: VFR. Chance SHRA, Slight chance TSRA.
&&
.CLIMATE...
Extreme heat and humidity will affect the region for the latter
half of the week, which could lead to some daily records. Below
are the current daily high and low temperature records in
jeopardy at our area climate sites.
Record High Temperatures:
July 1:
KBTV: 96/2018
KMPV: 92/2018
KPBG: 94/1968
KMSS: 94/2018
July 2:
KBTV: 97/2018
KMPV: 90/2018
KMSS: 94/2018
July 3:
KMPV: 91/2002
Record High Minimum Temperatures:
July 1:
KBTV: 76/2018
KPBG: 73/1971
KSLK: 69/2018
July 2:
KPBG: 77/2002
KSLK: 68/2002
July 3:
KBTV: 76/1911
KPBG: 73/2002
July 4:
KPBG: 71/1973
KSLK: 67/1952
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Heat Advisory until 7 PM EDT Friday for VTZ003-004-006>008-010-
016>020.
Extreme Heat Warning until 7 PM EDT Friday for VTZ001-002-005-
009-011-021.
NY...Heat Advisory until 7 PM EDT Friday for NYZ026-027-029>031-034-
087.
Extreme Heat Warning until 7 PM EDT Friday for NYZ028-035.
&&
$$
WHAT HAS CHANGED...Danzig
DISCUSSION...Danzig/Storm
AVIATION...Storm
CLIMATE...Danzig/NWS BTV
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