131
FXUS61 KBTV 051815
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
215 PM EDT Sat Jul 5 2025

.SYNOPSIS...
Warmer conditions are expected over the rest of this weekend with
high temperatures climbing into the upper 80s to mid 90s on Sunday.
A cold front will shift south on Monday bringing higher chances for
showers and thunderstorms, followed by more seasonable
temperatures. The rest of the week will feature hit-or-miss,
afternoon showers and thunderstorms.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
As of 156 PM EDT Saturday...** Heat Advisory in Effect from
Noon through 8 PM Sunday for the Champlain Valley and portions
of the Connecticut River Valley **

A beautiful evening is in store with temperatures in the upper 70s
to low 80s and comfortable dewpoints in the 50s. Radar is
showing some light returns are some precipitation spreads
southward from Quebec, but observations showing most of this is
not reaching the surface. Have continued with some 10 to 30
percent PoPs this evening near the International Border, but
any showers would be light and most parts of our forecast area
will remain dry. Otherwise, expecting broken to overcast skies
with high clouds spilling southward.

Overall synoptic stage is set for a brief but dangerous warmup
starting tonight and peaking tomorrow (Sunday). A Bermuda high
is in place well to our southeast with strong ridging over the
eastern US. A stream of Gulf moisture advecting north and east
will transport warm and muggy air into the northeastern US
starting tonight. Overnight temps tonight will range from 60 to
70 deg F, which is noticeably warmer than last night.

Exactly how warm we get Sunday will depend on both cloud cover
coverage and thickness along with how much moisture is present in
the low to mid levels. At this point, the NAM has slightly higher
low-level moisture and dewpoints, and thus slightly cooler surface
temps. Meanwhile, the GFS and the ECMWF mix down some drier air from
the mid-levels, bringing surface temps slightly higher and dewpoints
slightly lower during the afternoon. Have continued with a blended
solution, which yields highs in the low to mid 90s in the Champlain,
Saint Lawrence, and Connecticut River Valleys and in the upper 80s
to around 90 in the northern Adirondacks and higher elevations of
eastern Vermont. Dewpoints will rise into the mid to upper 60s,
which will result in muggy conditions with uncomfortable humidity
levels. Overall apparent temperatures will max out in the mid to
upper 90s over the Champlain Valley and eastern Connecticut River
Valley, where a Heat Advisory remains in effect from noon to 8 PM
Sunday. Elsewhere, heat indices will rise into the upper 80s to low
90s.

In addition to heat Sunday, will be watching a tight boundary that
is forecast to drop southward just to our north Sunday, bringing
some winds and a conditional threat for some showers and
thunderstorms to our northern counties. A 40 to 45 knot
southwesterly low level jet located just to the south of the
boundary will move over the Saint Lawrence Valley, which will create
some surface wind gusts 20 to 30 mph over the area Sunday,
especially over the Saint Lawrence Valley. The heat and humidity
will yield SBCAPE up to 1500 J/kg Sunday afternoon. Most of our
area will still be under the influence of ridging Sunday,
however if the sharp boundary moves south into our area or if
any outflow boundaries move south, it would support the
development of some afternoon/evening showers and thunderstorms.
Best chance of this would be along the International Border.
Best shear will be displaced to our north, but areas near our
northern border will see 35 to 45 knots 0-6 km bulk shear, which
would support organized updrafts if any convection were to
materialize. The threat overall is very conditional, with a
potential mid-level inversion present on some soundings that
could greatly limit instability, and still some uncertainty on
timing of the front and location.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 156 PM EDT Saturday...Sunday night into Monday, confidence
increases that the front will drop southward into our area, though
there still remains some question as to whether the front will
linger over our area or quickly push south. Given that many
ingredients are lining up for heavy precipitation along the front,
the speed of the front will play a crucial role in our
hydrology threat. Along and ahead of the front, precipitable
water values will rise to 1.9+ inches, which is 2 to 2.5
standard deviations above normal for our area this time of year.
Deep warm cloud depths (in excess of 13 kft) will promote
efficient rainfall processes, while the orientation of the flow
parallel to the front presents increased potential for training
cells. Deterministic models suggest best precipitation potential
will be Monday to early Monday night. Increased diurnal
instability during the day Monday will further increase
precipitation rates in any thunderstorms that develop. Given
the wide range of solutions among the individual ensemble
members, it`s difficult to peg down exact precipitation amounts.
However, the 06Z and 12Z suite of models are lining up on the
conservative side with highest probabilities in the 0.25 to 0.75
inch range for Monday. Any thunderstorms or training would
result in locally higher amounts. So overall at this point,
keeping a close eye on the front for Monday, but at this point
not overly concerned about hydro impacts given these forecast
rainfall amounts.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 140 PM EDT Saturday...The long term forecast heading into
mid to late week looks to begin an unsettled period of weather.
Temperatures will remain slightly above average with humid, but
not oppressive air. Confluent flow created by high pressure
over the deep south, and a broad trough over central/eastern
Canada will draw shower and thunder chances through much of mid-
late week. The best chances for any dry days will be Tuesday
and Wednesday as moisture will take time to recover behind the
Monday afternoon. A few shortwaves look ride along the upper-
level trough Thursday and Friday. However, the amplification of
the main trough still remains uncertain amongst the ensembles.
The GEFS and GEPS indicate a more broad trough which would allow
for daily precipitation chances from periodic shortwave
passages. However, the EPS is more amplified with a more defined
precipitation chance Thursday afternoon. The interaction
between the Monday afternoon boundary and current Tropical Storm
Chantal will help give a better picture as to what the upper-
level flow pattern will be going forward. While no impacts are
expected from Chantal, a slower system will stall the boundary
across southern New England and lead to a quasi- stationary
blocking pattern, whereas a more progressive system will keep
moisture moving leading to potentially drier conditions Tuesday
and Wednesday. We will continue to monitor any changes going
forward.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Through 18Z Sunday...High confidence in VFR conditions through
the entire TAF period at all terminals. Mid-upper level clouds from
some showers and storms earlier across eastern Ontario, along
with some haze and smoke are drifting across the region. No
terminal impacts are expected, but the haze and smoke may lead
to brief vsby reductions to 6SM. Otherwise, calm conditions are
expected with a brief light shower possible at MSS/EFK through
the evening, though no impacts are expected. Winds will be
south/southwesterly generally near 10 knots west of the Greens,
and variable east of the Greens through the next 18 hours.
Tomorrow, gusts will increase from the southwest at MSS/SLK to
near 25 kts by 16-18Z ahead of a frontal boundary. The LLWS
threat has decreased, with the exception of a brief period
overnight at PBG.

Outlook...

Sunday Night: VFR. Chance SHRA, Slight chance TSRA.
Monday: Mainly VFR, with local MVFR possible. Chance SHRA, Chance
TSRA.
Monday Night: Mainly MVFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
Tuesday: Mainly MVFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
Tuesday Night: Mainly VFR, with local IFR possible. Slight chance
SHRA.
Wednesday: Mainly VFR, with areas MVFR possible. Slight chance
SHRA, Slight chance TSRA.
Wednesday Night: Mainly VFR, with local IFR possible. Slight
chance SHRA, Slight chance TSRA.
Thursday: MVFR/IFR conditions possible. Chance SHRA, Chance TSRA.

&&

.CLIMATE...
Forecast high temperatures for Sunday will bring us within a few
degrees of record temps for a few sites. Here are the record
high temperatures for Sunday:

Max Temp Records
Date     KBTV     KMPV     KMSS     KPBG     KSLK
07-06  95|2010  91|2010  95|1993  93|2010  91|1933

Here are the record high minimum temperatures for Sunday:

High Min Temp Records
DateKBTV     KPBG     KSLK
07-06  74|1897  74|2010  65|1931

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Heat Advisory from noon to 8 PM EDT Sunday for VTZ001-002-005-
     009-011-021.
NY...Heat Advisory from noon to 8 PM EDT Sunday for NYZ028-035.

&&

$$
SYNOPSIS...Duell
NEAR TERM...Duell
SHORT TERM...Duell
LONG TERM...Danzig
AVIATION...Danzig
CLIMATE...NWS BTV