541
FXUS61 KBTV 121127
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
727 AM EDT Sat Jul 12 2025

.SYNOPSIS...
Isolated showers and thunderstorms will redevelop today as the
region remains in a humid and unstable pattern. A weak frontal
passage will increase chances for showers and thunderstorms later
Sunday into Monday. Drier, but continued hot and humid weather, is
expected for the remainder of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 720 AM EDT Saturday...A few isolated showers in Rutland
county that may survive a trek across Windsor county. In
addition, developing SHRA/TSRA in the Hudson Vly making a slow
trek toward VT. HRRR has these dissipating in the next few hours
but have made changes in forecast for some brief -shra in the
morning. Otherwise, continue with previous forecast.


Previous discussion...Heat and humidity will build today as we
start the warming trend that will linger into next week. 925mb
temperatures will approach 22- 24C this afternoon, just a few degrees
warmer than yesterday. Hence anticipate highs to range from the mid
80s in the higher elevations to the low 90s in the wider valleys.
With dewpoints well into the 60s and likely even topping 70F in some
spots, still anticipate heat index values in the low to mid 90s.
Some locations could top 95F, these should be fairly localized and
for just a short duration, thereby keeping us just below Heat
Advisory levels. Still, it`ll be a warm and muggy day, so please
make sure to take appropriate heat safety precautions.

Still anticipate isolated to scattered showers and thunderstorms to
develop by this afternoon. Forcing will be weak, but with sufficient
instability (mean CAPE values of 850-1500 J/kg), expect there will
be enough terrain-driven lift for thunderstorm development. Shear is
much more modest, 15 to 25 kt at best, so severe weather is not
anticipated. However, there is a non-zero chance for locally
stronger convection, which might be capable of producing strong to
marginally severe winds. Heavy rain will be possible as well, with
rainfall rates locally exceeding 0.25 in/hr at times. Any convection
should wind down Saturday evening as diurnal heating is lost. It
will stay a fairly muggy night though, with lows in the mid 60s to
low 70s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
As of 207 AM EDT Saturday...Sunday continues to look like the
potentially more impactful day for isolated severe thunderstorms and
flooding. It`ll be another warm and humid day, allowing for ample
instability, particularly over northern NY where mean SB CAPE values
of 1000-2000 J/kg are expected. Further east, an inversion 850mb
will temper instability and limit convective potential. Meanwhile, a
warm front will lift across the region Sunday morning, followed by a
slow-moving cold front which will very gradually push eastward from
the Great Lakes late Sunday into Sunday night, and then eventually
through our area on Monday. Moisture will pool ahead of the cold
front, and expect a prolonged period of PWATs approaching 1.75+ inch
by Sunday afternoon/night. The copious moisture, ample instability,
and frontal forcing will be enough for scattered to perhaps numerous
showers and thunderstorms to develop Sunday afternoon, likely
lingering through SUnday night as the cold front makes its slow
eastward progress. Deep layer flow will be southwest and parallel to
the front, keeping eastward progress of both the front and any
associated convection slow. Shear will be somewhat better than on
Saturday, though still just 15 to 25 kt at 0-6km. The front should
finally push through our area on Monday, keeping the threat showers
and thunderstorms capable of producing heavy rain in the forecast as
PWATs will remain close to 2 inches until the front finally exits.
Note that we remain in a Marginal Risk in SPC`s latest Day 3 Severe
Weather Outlook, and likewise in WPC`s Marginal Risk for Excessive
Rainfall for both Sunday and Monday. Both days will need to be
monitored closely, both for severe potential and any flash flooding
risk, especially in areas that have received recent heavy rainfall.

Temperature wise, Sunday should see highs quite similar to Saturday,
perhaps just a degree or two cooler owing to more cloud cover.,
Still, dewpoints will be in the 60s and 70s, keeping heat index
values close to that 95F Heat Advisory threshold. One good thing is
that it does look like we should have a bit more wind, which may
help make it feel a little less oppressive. Sunday night will be
warm and muggy again, but Monday will likewise be a few degrees
cooler than Sunday as the front moves through. The most noticeable
change will be lowering dewpoints, back out of the 70s and into the
50s and 60s.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 207 AM EDT Saturday...Shortwave and associated frontal boundary
largely east of CWA by Monday night so drying with clearing skies
but not much change in the airmass.

Eastern CONUS Heat ridge builds again for Tuesday and Wednesday with
warmest day with 850mb temps possibly reaching 17-20C and 925mb
temps reaching 23-25C at its peak. Dewpoints likely in the 60s for
much of the duration and even some low 70s.

There are timing differences with the breakdown of the upper heat
ridge and northern stream disturbances. GFS is customarily quick
while ECMWF and Canadian are a bit slower due to strength of the
heat ridge.

Current thinking is front lies across the St. Lawrence River Vly on
Thursday with close proximity, surface heating and instability that
showers/t-storms develop more in northern NY than in southern CWA.

Thr front with potential several small waves in parallel WSW flow
will slowly move into and through CWA Thu ngt-Fri with rich PWATS of
1.75-2 inches, thus potential for heavy rain producers so we`ll need
to monitor closely.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Through 12Z Sunday...VFR conditons for all sites as any morniog
fog has dissipated. Some isolated showers will move across/nr
KRUT for a few hours this morning. Otherwise...VFR with SCT
-TSRA possible between 20-02z across TAF sites except KMSS.

Aft 06z...some stratus and fog for central/eastern VT like KMPV
and stratus at KSLK but enough winds aloft that I think no fog
formation for KSLK.

Surface winds for most will be less than 10 kts for all Taf
sites.


Outlook...

Sunday: VFR. Chance SHRA, Chance TSRA.
Sunday Night: Mainly VFR, with local IFR possible. Likely SHRA,
Chance TSRA.
Monday: Mainly VFR, with local IFR possible. Chance SHRA, Chance
TSRA.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. Slight chance SHRA.

&&

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

&&

$$
SYNOPSIS...Hastings
NEAR TERM...Hastings/SLW
SHORT TERM...Hastings
LONG TERM...SLW
AVIATION...SLW