348
FXUS61 KBTV 161727
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
127 PM EDT Sun Aug 16 2026

.WHAT HAS CHANGED...
As of 237 AM EDT Sunday...

Beneficial rainfall remains on track for tonight. Slightly
greater potential for a thunderstorm Monday afternoon/evening.

&&

.KEY MESSAGES...
As of 237 AM EDT Sunday...

1. Pleasant conditions through the daylight hours today.
Widespread showers with beneficial rainfall tonight will be followed
by scattered showers and localized thunderstorms Monday.

2. A narrow ridge of high pressure and seasonable warmth for
Tuesday will give way to another weak frontal system that brings
shower and thunderstorm chances Wednesday.

3. Climatological conditions persist through the second half of
the week.

&&

.DISCUSSION...
As of 237 AM EDT Sunday...

KEY MESSAGE 1: A mid-level trough and the associated warm air advection
ahead of this feature should produce enough ascent for widespread
showers this evening, generally starting in New York and spreading
north and east with time. A band of heavier rainfall rates still
appears possible overnight, and model guidance that shows this
feature continues to favor northern and northeastern Vermont
primarily with greater likelihood of rainfall amounts of around 0.5"
to 1" and locally greater than 1". Meanwhile a quarter inch or less,
with many areas seeing only 0.1" or so, is expected for most areas
through the nighttime hours. While we continue to expect a surge of
PWAT and warm cloud depth values that typically are associated with
our heavy rainfall events, instability looks scant (Most Unstable
CAPE < 300 J/kg) and rain showers fast moving such that downpours
will be very brief in nature. The upper level pattern doesn`t appear
conducive to a heavy rain event, as there will be a split in the
flow with two competing areas of forcing; one passing to our north,
which will primarily affect our region, and another wave well to our
south, where the primary deep moisture and convective threat will
lie.

Perhaps more interesting will be the showers that develop during the
day tomorrow, which may be capable of producing lightning as the
environment becomes marginally conducive for thunderstorms. Overall
the threat for any strong thunderstorms is very low and severe
weather is not expected. The greatest risk area seems to be from
eastern Essex County, New York and into the southern Champlain
Valley, although broadly a 20-25% chance of thunder during the
afternoon exists for the Adirondacks and much Vermont. Dew points
increasing into the mid and upper 60s and limited sunshine will aid
in some modest surface-based instability with showers developing
with relatively shallow cloud bases. PWAT remains elevated (roughly
1.4 to 1.6 inches) with ensemble mean surface based instability
climbing into the 750-1250 J/kg range during peak heating in
northeastern New York, where a subtle convergence line should set up
to help showers blossom and organize. Effective shear looks
relatively low (25 or so knots), limiting the potential for any
stronger storms, although terrain driven convergence in the western
Champlain Valley could help strengthen cells that move through. The
showers will gradually move south and eastward, as the
boundary/trough exits Vermont sometime in the evening. Rainfall will
be highly variable, with some localized areas likely seeing around
an inch of new rainfall but most areas seeing only an additional few
hundreths to a quarter inch.

KEY MESSAGE 2: The next noteworthy period of weather will be on
Wednesday when there is broad consensus that a fairly weak cold
front will pass through the Northeast. Timing of the front is
generally appears to be during the day with primarily chances for
showers and thunderstorms during the afternoon and evening hours.
The details and potential for multiple boundaries to move through
the region will need to be hashed out in the coming days. That being
said, some deterministic model guidance suggests the pre-frontal
environment will be devoid of instability and moisture such that
little in the way of thunderstorm, let alone shower, activity will
occur. Per ensemble guidance, the risk of thunderstorms, along with
rain chances, is perhaps a bit higher in the St. Lawrence Valley
than areas to the east, but we`ll watch trends in the coming days.

KEY MESSAGE 3: Lingering showers will move out through the day
Thursday, as broad cyclonic flow slowly migrates eastward. After
the system moves off, a period of drier weather looks to return
for the latter half of the week. Daytime temperatures will
fluctuate near climatological normals in the mid 70s, with
overnight lows falling into the low 60s. There is potential for
another system to sweep through next weekend bringing some
sustained showers. We`ll continue to monitor as the models lock
in.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Through 18Z Monday...Dry conditions through the daylight hours today
with southeasterly winds 5-15 knots, more east-northeasterly 5-10
knots at site MSS. Widespread showers with beneficial rainfall
tonight will be followed by scattered showers and localized
thunderstorms Monday. As rain showers arrive this evening and
tonight, we`ll see a general trend towards MVFR or lower ceilings,
reaching widespread MVFR cigs by 01Z-04Z Monday. Winds should
persist out of the south, with sites MSS and SLK picking up a more
southwesterly component around 05Z-08Z. Southerly flow will likely
remain channeled and gusty through the Champlain Valley, gusting
20-25 knots at site BTV throughout the night tonight and early
Monday morning. IFR ceilings are possible sometime tonight and into
Monday morning as well, though some uncertainty remains. Most likely
spots for IFR ceilings will be SLK and MSS with that southwesterly
wind, though no site is out of the question. As of this afternoon,
confidence is not high enough to include in the TAF. Most model
soundings are not as saturated as probabilistic data might suggest.
As the showers approach and we get additional observations from
areas upstream, this may increase confidence in one direction or
another. LLWS is also possible as a southwesterly low level jet
crosses the region around 02Z-12Z Monday. Most likely spots for low
level wind shear are BTV, SLK, MPV, EFK, and RUT, though brief LLWS
may occur elsewhere as well.


Outlook...

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

&&

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

&&

$$

WHAT HAS CHANGED...Kutikoff
DISCUSSION...Langbauer/Kutikoff
AVIATION...Storm