290
FXUS61 KBTV 181840
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
240 PM EDT Sat Jul 18 2026
.WHAT HAS CHANGED...
As of 240 PM EDT Saturday...
Risk of strong to severe thunderstorms has decreased for the
rest of today, with lower thunderstorm chances as well.
&&
.KEY MESSAGES...
As of 240 PM EDT Saturday...
1. While the threat of damaging winds in our area has
decreased, rounds of showers with a few thunderstorms will continue
into this evening. Meanwhile, near surface smoke has returned
to much of our region but will be replaced by cleaner air and
low humidity for Sunday and Monday.
2. Chances of showers and a few thunderstorms return for later
Tuesday into Wednesday, otherwise mainly fair and seasonable weather
is expected to end the work week.
&&
.DISCUSSION...
As of 240 PM EDT Saturday...
KEY MESSAGE 1:
A vigorous shortwave trough diving southeastward over eastern
Ontario alongside a moderately deep low pressure system is
promoting widespread precipitation and areas of deep convection
across the Northeastern US. The system`s warm front is having a
hard time pushing east/northeastward, such that isentropic lift
has been generating steady rain with embedded downpours across
northern New York and Vermont. As a result, the possibility of
our region becoming destabilized via surface heating has greatly
diminished today`s potential severe weather event. The limited
threat area is trending towards the St. Lawrence Valley where
MLCAPE is progged to surge to near 1000 J/kg by 7 PM amidst
partial clearing, which could be sufficient for localized
damaging wind if there is some storm organization/linear
convection in the late afternoon/early evening. This area is the
most likely to see any thunderstorm activity as well, although
some thunder can`t quite be ruled out farther east into the
Adirondacks and perhaps northern portions of Vermont given
Otherwise, the rest of the day is shaping up to be merely
showery and breezy, with rain-cooled air and thick clouds making
for the coolest day we have seen since June.
As the system`s cold front presses eastward through our region
between about 9 PM and 1 AM, winds will shift westerly and trend
northwesterly, ushering in a return to dry air. Relatedly, most of
the wildfire smoke that has pushed northward into northern New
York and Vermont, especially higher elevations, this afternoon
will be steered out of the region. Unfortunately, a different
plume of smoke from the northwest will likely push into northern
New York overnight, which could once again degrade air quality.
At this time, the concentrations look less significant than what
we are seeing currently For now, Air Quality Alerts remain in
effect today; the New York State Department of Environmental
Conservation at https://on.ny.gov/nyaqi and Vermont Agency of
Natural Resources web site at https://dec.vermont.gov/air-
quality/local-air-quality-forecasts will have more information.
Aside from any lingering smoke concerns, another extended
stretch of high pressure and pleasant temperatures are
anticipated Sunday through Tuesday morning.
KEY MESSAGE 2: Overall, deterministic solutions and their accompanying
ensemble blends support a persistence forecast into the middle and
latter portions of next week so I`ll continue with this idea. The
main weather feature of note will be the approach/passage of a
frontal system later Tue/Wed. At this time, the best forcing looks
to arrive in the overnight hours thus limiting the threat of severe
weather. However, PWAT values do climb AOA 1.5 inches, so locally
heavy downpours will be possible with any deeper convective cores.
Behind the front, surface high pressure and a much drier airmass
arrive for late week (Thu/Fri) with fair/dry wx returning. Model-
averaged 925 hPa thermal profiles through the period support
pleasantly seasonable mid-summer temperatures with daily highs in
the mid 70s to lower 80s and overnight lows in the mid 50s to lower
60s.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Through 18Z Sunday...Mainly VFR this afternoon with scattered
thunderstorms as a warm front approaches. Some TSRA will
continue to develop through the evening hours, mainly in the
south and west portions of our CWA, as indicated by the PROB30s
for RUT and SLK. Other terminals could see some locally heave
downpours that bring down visibilities for a short period of
time. Outside of the showers, we will see primarily southerly
winds with gusts into the mid 20 knots. Showers will clear
after 00z.
Outlook...
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Likely SHRA, Chance TSRA.
Tuesday Night: Mainly VFR, with local IFR possible. Definite
SHRA, Slight chance TSRA.
Wednesday: Mainly MVFR, with areas IFR possible. Likely SHRA,
Chance TSRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA, Slight chance TSRA.
Thursday: VFR. Slight chance SHRA, Slight chance TSRA.
&&
.MARINE...
Seasonably strong south-southeast winds have been mixing on Lake
Champlain during the day today, resulting in observed winds at
Colchester Reef as high as 27 knots sustained early this
afternoon and likely large waves on both the broad lake and
northern waters in the 2 to 4 foot range. Peak winds will
persist in a 20-30 knot range on the broad lake through early
evening before diminishing and then picking up tonight out of
the northwest behind a cold front. These winds overnight will
also potentially reach 25 knots and produce rough waves with a
strong westerly component and deeper mixing will help produce
gusty conditions. Gradually winds and waves will subside during
the Sunday morning timeframe.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Air Quality Alert until 11 PM EDT this evening for VTZ001>011-
016>021.
NY...Air Quality Alert until midnight EDT tonight for NYZ026>031-
034-035-087.
&&
$$
WHAT HAS CHANGED...Kutikoff
DISCUSSION...JMG/Kutikoff
AVIATION...Langbauer
MARINE...Kutikoff
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