176
FXUS61 KBTV 191121
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
721 AM EDT Tue May 19 2026

.WHAT HAS CHANGED...
As of 236 AM EDT Tuesday...

Winds were increased for today and tonight as warmer temperatures
help mix stronger winds aloft to the surface.

&&

.KEY MESSAGES...
As of 236 AM EDT Tuesday...

1. Well above normal temperatures expected on Tuesday with
much cooler weather expected on Wednesday and Thursday.

2. Strong to locally severe thunderstorms possible Tuesday
afternoon and evening.

3. Cooler and drier conditions are favored Thursday and Friday
before a transition back to seasonable temperatures and a wetter
pattern.

4. Seasonable temperatures and increasing chances of
precipitation expected for the weekend into early next week.

&&

.DISCUSSION...
As of 236 AM EDT Tuesday...

KEY MESSAGE 1: Continued warm air advection will set the stage for
unseasonably warm temperatures on Tuesday. The latest NBM shows high
potential for 90 degree weather, however, much of the other guidance
and MOS is showing temperatures likely plateauing in the mid to
upper 80s. Cloud cover and convection will be a huge factor in
determining how warm we get as a lot of guidance suggests partly to
mostly cloudy skies. Any convection would increase cloud cover and
any precipitation would drop temperatures significantly. Still,
there is overwhelmingly high confidence in high temperatures being
15 to 20 degrees above normal. On Wednesday, a cold front will
likely push through the region during the morning hours which will
limit daytime heading with strong cold advection expected to follow
in the wake of the front. We could still warm into the 80s across
eastern Vermont but will likely be in the 70s for most of Vermont
and New York based on the timing of the frontal passage. Thursday
will be 10-20 degrees colder than Wednesday as we will see
temperatures struggle to climb into the mid 50s to lower 60s. North
winds in the 10-20 mph range will help make it feel a bit blustery,
especially after the recent warmth. Most clear skies should help it
feel a little warmer given the late May sun angle.

KEY MESSAGE 2: The convective potential for Tuesday continues to remain
very conditional. A lot of the machine learning and AI tools are
showing modest probabilities (15-30%) for severe weather Tuesday
afternoon and evening while the latest deterministic guidance shows
rather lackluster instability. There is high confidence in around 50
knots of deep-layer shear as we have a strong 500 jet move overhead
but the thermodynamic profiles keep fluctuating from model run to
model run. Even though temperatures are expected to warm into the
mid to upper 80s and dewpoints rising in the lower to mid 60s, the
mid-level lapse rates between 850 mb and 500 mb aren`t exactly what
you want to see to maximize severe potential. In addition, no
notable surface convergence outside of orographic lifting is
expected with the cold front not expected to come through until
Wednesday morning. There will be some weak height falls under
anticyclonic flow aloft and a weak shortwave trough pushing through
which will give up some deep layer support but getting storms to
initially develop will be difficult. The main focus, initially, will
be across the higher terrain and along lake breezes as this could
create some surface convergence and the upper level support could
take over from there.

There may be residual cloud cover from overnight convection across
western New York which may stunt surface heating. Should this occur,
instability values may underperform further and lead to little to no
thunderstorm activity. Hence the condition potential. Largely
unidirectional wind profiles with slight curvature in the Champlain
Valley is expected which likely makes Tuesday a wind threat. High
LCLs will strongly inhibit tornado potential with high freezing
levels also making severe potential very difficult to come by. The
main window for convection will be between 4 and 8 PM with
instability waning rapidly following sunset.

KEY MESSAGE 3: Winds weaken Thursday night with skies clearing; this
may be a period of concern for some frost outside the Champlain
Valley with lows in the mid/upper 30s for many locations, and low
40s for the Champlain Valley. Temperatures begin to warm up on
Friday with northwest flow weakening, high temperatures will reach
the 60s areawide. A slow warming trend is then expected through the
weekend into Monday.

Models begin to split on precipitation timing heading into the
weekend. Consensus maintains some chances of showers increasing
Saturday with more widespread rain Sunday. However, a number of
models are beginning to hold onto the ridge longer delaying
precipitation onset until the late weekend. Either way, a pattern
shift to deep return flow from the Gulf Coast northeastward into the
Northeast is appearing probable. This flow pattern would result in
multiple days of rain potential once it sets up.

KEY MESSAGE 4: There continues to be considerable differences in both
ensembles and deterministic models in how shower chances play out
for the upcoming holiday weekend. Ensemble members of both the GEFS
and ECMWF are roughly split equally on whether waves of precipitation
will cross the area Saturday into Sunday. The deterministic ECMWF
also favors a wetter solution. Meanwhile, the remaining ensemble
members along with the GFS and CMC keep ridging more firmly in
place, with the axis running just to our east. This would keep rain
shunted to our south and west through the day Saturday and most of
Sunday, then trending rainy for Memorial Day. With this much
uncertainty, have stayed with the NBM solution for now. Either way,
temperatures will be seasonable with highs mainly in the 60s and
lows in the 40s.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Through 12Z Wednesday...This morning, some showers are moving
into northern New York with a focus on MSS and SLK through 16Z.
More nebulous are chances as the area of showers track into the
Champlain Valley - have about 30% chance of showers 15-21Z.
After 18Z, isolated to scattered showers/thunderstorms are
possible, some of which may be strong to perhaps severe.
Coverage/timing is too uncertain at this point to include any
mention in the TAF, but MVFR/IFR conditions will be possible in
any thunderstorms. Surface winds become light and variable
around 5 kt this evening. However, a LLJ moving overhead will
allow for periods of LLWS at all terminals overnight. Surface
winds increase out of the S/SW after 14z Tue, gradually shifting
toward the W/SW with gusts of 18-25 kt expected. LLWS will
become pervasive overnight as LLjet spread across northern New
York and much of Vermont ahead of an approaching cold front.
Showers will begin at MSS after 09Z.

Outlook...

Wednesday: VFR. Chance SHRA.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. Chance SHRA.
Saturday: VFR. Chance SHRA.

&&

.MARINE...
As of 236 AM EDT Tuesday...

A Lake Wind Advisory remains in effect for the Broad Waters of
Lake Champlain. Winds are expected to increase this morning out
of the south with sustained speeds 15 to 20kts and gusts around
25kts. These stronger winds will continue through 8 AM and will
diminish to 15 knots or less until the early afternoon; winds
then increase again as faster winds aloft mix to the surface.
Gusts in excess of 20kts are probable before flow turns more
southwesterly. South winds return tonight with stronger gusts
possible. A front will pass through the region Wednesday
resulting in a wind shift out of the north with gusts up to
30kts.

&&

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

&&

$$

WHAT HAS CHANGED...Boyd
DISCUSSION...Boyd/Hastings
AVIATION...Boyd/Hastings
MARINE...Clay