820
FXUS61 KBTV 261417
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1017 AM EDT Sat Jul 26 2025

.SYNOPSIS...
Widespread smoke and haze is present in most of northern Vermont
today, with otherwise seasonable temperatures and dry weather
expected today. A couple of chances for rain and isolated
thunderstorms exists late tonight into Sunday, as hotter and
humid conditions persist through Tuesday. Conditions then trend
substantially drier, with below normal temperatures expected
during the later part of the week along with dry weather.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 1012 AM EDT Saturday...Quick updates to the forecast this
morning as Air Quality Alerts have been issued for our entire
forecast area through tonight. The Air Quality Alerts for
Vermont are in effect until 11 PM, while the Air Quality Alerts
in northern New York are in effect until midnight tonight. For
additional information, please visit the New York State
Department of Environmental Conservation website at
https://on.ny.gov/nyaqi and/or the Vermont Agency of Natural
Resources web site at https://dec.vermont.gov/air-
quality/local-air-quality- forecasts. Previous discussion
follows...

Main story for today is the combination of fog and smoke early
in the day, primarily east of the Adirondacks through much of
northern Vermont. Smoke has been forced to the surface after it
advected southward into the region and will probably not mix out
very quickly given light winds. Model soundings show deep
mixing developing towards noon which lead to some improvement
during the afternoon. So expect degraded air quality, as of this
writing in the unhealthy category for much of the
aforementioned area, will linger. As such, the forecast shows
mention of smoke into the daytime hours. At the very least,
there will be haze today with otherwise sunny and dry conditions
as the air mass otherwise will be rather pleasant. Light
southerly flow will increase slightly towards evening.

It remains a challenging forecast scenario for late tonight into
tomorrow with two periods of shower and thunderstorm chances, each
with fairly low predictability. Neither one looks particularly
impactful with regards to potential for flash flooding or severe
thunderstorms, but both threats will need to be monitored despite
low risk.

The early Sunday morning forcing for widespread showers with heavy
rainfall, especially in embedded thunderstorms, still looks
relatively straightforward; however, it remains uncertain how far
north this area of rain will go as a strong upper level wave crosses
the region from west to east. Several pieces of model guidance show
heavy rain moving into the Adirondacks during the predawn hours and
peeling slightly south of due east over the southern Green
Mountains; generally chances of rain are higher as one goes
southward. The environment will likely feature rich moisture
supportive of heavy rainfall rates, but just to the north there will
be a plethora of dry air aloft. A lot like a winter storm, there is
a lot of spread in possible precipitation amounts. For instance, in
Newcomb, New York where heavy rainfall is probably more likely than
anywhere else in our forecast area, amongst model guidance the
interquartile range of six hour precipitation ending 8 AM
Sunday is from 0.1" to 0.77" with a few models showing 1 to 2.5"
of rain. Footprints of 1-1.5" of rain within 6 hours are
possible, with areas like Newcomb having about a 70% chance of
reaching an inch of rainfall per the HREF guidance Ensemble
Agreement Scale.

Later in the day as temperatures warm into the 80s with dew points
in the 65 to 70 range, we should see instability build. Per HREF-
calibration chances of thunder, isolated to scattered thunderstorms
across northern New York and western Vermont looks reasonable. That
would be consistent with a surface weather pattern featuring a weak
triple point feature in the St. Lawrence Valley and attendant
warm front draped across the Champlain Valley. In the warm
sector, instability should become moderately high, approaching
2000 J/kg Sunday afternoon, with a sharply lower amount of CAPE
probable farther south and east. The possible trigger for
convection may be a combination of another embedded trough
coming across the region as flow aloft turns more northwesterly
and topographically-enhanced convergence. This pattern does not
suggest a heavy rain threat, but northwesterly deep layer shear
and sufficient instability could support a gusty wind threat as
DCAPE will probably be fairly high. It is unclear if storms will
gain much organization, but we`ll monitor trends in the
convective allowing models which currently show little
predictability in what will transpire. &&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 1012 AM EDT Saturday...This period will be characterized
by seasonably hot and humid conditions as temperatures climb
into the upper 80s to low 90s. Humid conditions in place Sunday
will help temperatures stay mild such that we start the day with
temperatures already in the mid to upper 60s in many locations.
Right now the forecast does look slightly less impressive than
this past Thursday as far as apparent temperatures, so while it
would not be surprising to need Heat Advisories, it is not
obvious that heat index values will exceed 95 anywhere. Ensemble
anomalies for the upper levels are also not as impressive as
the low level heat would suggest, which could support some
diurnally driven convection. For now, PoPs are too low to
include mention of thunderstorms, but that could be something to
watch moving forward as a cold front, or pre-frontal trough,
moves into the area and interacts with the likely moderately
high instability over the region.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 316 AM EDT Saturday...This period will be characterized
by seasonably hot and humid conditions as temperatures climb
into the upper 80s to low 90s. Humid conditions in place Sunday
will help temperatures stay mild such that we start the day with
temperatures already in the mid to upper 60s in many locations.
Right now the forecast does look slightly less impressive than
this past Thursday as far as apparent temperatures, so while it
would not be surprising to need Heat Advisories, it is not
obvious that heat index values will exceed 95 anywhere. Ensemble
anomalies for the upper levels are also not as impressive as
the low level heat would suggest, which could support some
diurnally driven convection. For now, PoPs are too low to
include mention of thunderstorms, but that could be something to
watch moving forward as a cold front, or pre-frontal trough,
moves into the area and interacts with the likely moderately
high instability over the region.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 210 AM EDT Saturday...Warm, humid conditions are expected
Monday night ahead of a cold frontal passage Tuesday morning. Expect
upper 60s to lower 70s for the broad valleys and mid 60s in cool
hollows. The front itself will cross with little fanfare as dry air
and early timing keep activity scattered. Cold air will take a bit
more time to displace the hotter air from Monday, and so another
toasty day ranging from the mid 80s north to 90s south is again
expected. There will at least be lower humidity filtering in.

Wednesday will likely be a pleasant day with isolated to scattered
showers and a few thunderstorms as temperatures climb into the mid
80s with upper 50s to lower 60s dewpoints. A thermally stronger cold
front will slide south as an anomalously strong and cool upper low
dives southwards. The front will again struggle with the moisture
department, and the lack of a well-defined surface feature will
prevent widespread activity in the absence of better instability
which will reside well south of us.

The rest of the extended will trend dry and cool as that upper low
makes its approach. Several models depict sub-540 dam thicknesses
from 1000-500mb and the 850mb 0 C line possibly grazing the
Northeast Kingdom, which is very impressive for this time of year.
Abundant sunshine and dry atmospheric conditions will likely allow
efficient warming into the 70s, and a sustained wind due to modest
pressure gradients will likely only produce somewhat below normal
nighttime lows. This fall-like pattern may bear watching for dry
relative humidity values against gusty northwest winds given many
areas are running 2-5" below normal for precipitation this summer.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
Through 12Z Sunday...Skies will trend clear, but wildfire smoke
will across the Champlain Valley and all of Vermont will be slow
to depart leading to MVFR visibilities for at least the first
few hours. Flow will be mostly terrain driven with upslope
northwest winds likely at KRUT and KMPV, or southwest lake
breezes at KBTV and southeast breezes at KPBG. Some element of
variability may also develop as southwest winds try to become
established, but after 00z, winds will trend light or terrain
driven. Clouds will remain FEW to SCT at or above 10000 ft agl,
although towards the end of the period clouds may lower in
western portions of the airspace.


Outlook...

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

&&

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

&&

$$
SYNOPSIS...Kutikoff
NEAR TERM...Duell/Kutikoff
SHORT TERM...Kutikoff
LONG TERM...Haynes
AVIATION...Haynes