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157
FXUS61 KBTV 121837
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
237 PM 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 SUNDAY NIGHT/...
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As of 125 PM EDT Saturday...Seasonably hot and humid conditions
will continue this afternoon into the remainder of the weekend
with showers chances increasing by Sunday. Temperatures today
will continue to be in the upper 80s to low 90s with heat index
values in the low to mid 90s as a brief surface ridge builds
in. Remember to follow appropriate heat safety precautions.
Across the area, agitated cumulus in the Adirondacks have
favored a more southwestlery flow with a southeasterly marine
layer to the east of the Greens, leading to a convergence
boundary along the spine of the Greens. Isolated showers and
thunderstorms have developed along this boundary along with
some terrain driven showers across the Adirondacks. Most of the
shower activity today will be diurnally terrain driven and will
gradually drift off the mountains later this afternoon moving
eastward. With the heat, current surface CAPE values are around
1500 J/kg, though without any real forcing mechanism and modest
shear only 15 to 20 kts, widespread showers, and any severe
potential, are unlikely. Surface flow with initial storm motions
will be slow moving leading to potentially localized heavy rain
and flooding. Precipitable water also remains on the higher
side around 1.5" with warm cloud depths near 10000 ft, which
continues the theme of the existing Marginal Risk Outlook for
Excessive Rainfall today. Rainfall rates may locally exceed
0.25"/hr at times. While the coverage for any thunderstorms will
generally be isolated to scattered, with the potential for
heavy rain, we will continue to monitor the trends into the
afternoon/evening. Beyond sunset, most of the shower activity
should wane as they will be diurnally dependent. A lingering
shower as the convergence boundary decays in eastern Vermont
will be possible into the evening. Temperatures overnight will
offer little relief from the heat this afternoon only falling to
the upper 60s in the higher-terrain, to low 70s in the
Champlain and St. Lawrence Valleys.

Sunday will feature continued heat and humidity values ahead of
an approaching frontal boundary Sunday afternoon with the
chances for more widespread showers and thunderstorms, some
could be severe. 925mb temperatures tomorrow will continue to be
in the +24-26C range with surface highs in the upper 80s to low
90s as the ridge axis crests overhead. Heat index values will
be in the low to mid 90s, though with approaching cloud cover
from the west, chances of higher heat index values will be lower
than today. With the heat, SBCAPE will once again be around
1000-2000 J/kg with slightly better shear around 20-25kts. An
850mb inversion, associated with a marine layer over eastern
Vermont, will generally keep a lid on any convection in Vermont
for most of the day before better forcing arrives in the evening
from a cold front. Pwats around 1.5-1.75"+ along with continued
slow surface flow will create conditions for localized flash
flooding across parts of New York. WPC again has a Marginal Risk
Outlook for Excessive Rainfall tomorrow in northern New York
and northern Vermont, with a slight risk for Excessive Rainfall
in parts of the Adirondacks. In addition to the heavy rainfall,
lake winds will gust to near 25 kts with channeled southerly
flow, and near 15 kts elsewhere.

While the boundary is technically a cold front, it will be far
from cooling things off. Temperatures will remain warm with
overnight lows barely making it into the upper 60s to low 70s.
The front will continue its slow move across the area only
reaching the Champlain Valley overnight.
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&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
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As of 125 PM EDT Saturday...Our overarching frontal system from
the weekend will continue to slowly move eastward Monday
reaching eastern Vermont by the late morning/early afternoon.
Heavy rain with continued pooling moisture will be the main
threat. Pwats will remain on the higher side near 2" on the GFS,
and 1.5-2" indicated on the NAM3K. Continued slow surface flow
could lead to some torrential downpours and isolated flash
flooding in eastern Vermont. The front will clear out Monday
evening with noticeably cooler temperatures and less muggy air.
Daytime temperatures will be in the upper 80s across northern
New York and the Champlain Valley, and in the 70s across eastern
Vermont where showers will be located. Overnight temperatures
will finally fall into the 60s areawide with dewpoints in the
50s.
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&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
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As of 125 PM EDT Saturday...The reprieve in temperatures and
dewpoints Monday evening into Tuesday morning will be short-
lived as a surface ridge will build in across the eastern CONUS
by mid week. 925mb temperatures will reach into the +23-25C
range, peaking on Wednesday. Moist air will return by mid week
as well with dewpoints likely in the 60s. Probabilities of
exceeding heat advisory criteria will peak on Wednesday around
40%. The ridge will break down between mid to late week with
temperatures falling closer to seasonable norms, though still
above average, ahead of a frontal system.

Another slow-moving frontal system will work its way into the
region by Wednesday night. Timing of this system remains in
question amongst the ensembles, but current thinking is that the
front becomes held up in the St. Lawrence Valley, based on low
height falls, Wednesday into Thursday and slowly moves across
the area Thursday into Friday. Given the potential slowness of
the system and persistence thinking from similar events
recently, there is a potential for heavy rain, so we`ll need to
monitor this closely.
-- End Changed Discussion --

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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Through 18Z Sunday...Lower ceilings this morning have given way
to scattered cumulus with bases around 3000-5000 ft agl. Winds
are mostly out of the south to southeast at variable speeds
ranging from 3 kts at KMSS to 12 knots at KPBG. Little change to
conditions are expected over the next 6 hours, but isolated to
scattered showers and thunderstorms could briefly reduce
ceilings to 2500 ft agl or visibilities between 1 and 5SM in
heavier activity. Convection will wane after 00z. Winds will
remain elevated overnight at 5 to 10 knots out of the south.
This should preclude fog, but if winds decrease enough, there
could be brief patchy fog from about 06z to 12z. Even absent any
fog, some lower stratus will shift into the region, especially
in eastern Vermont, which will reduce ceilings towards 1500-5000
ft agl, locally below 1000 ft from about KMPV southwards,
through about 15z. Beyond 12z, a trough will approach, which
will likely be producing showers and storms already that will
shift east.

Outlook...

Sunday Night: VFR. Likely SHRA, Chance TSRA.
Monday: Mainly VFR, with areas MVFR possible. Likely 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, Slight chance TSRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Thursday: VFR. Chance SHRA, Slight chance TSRA.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...Danzig
NEAR TERM...Danzig
SHORT TERM...Danzig
LONG TERM...Danzig
AVIATION...Haynes