746
FXUS61 KBTV 182340
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
740 PM EDT Mon May 18 2026
.WHAT HAS CHANGED...
As of 252 PM EDT Monday...
No significant changes have been made at this time. Well above
normal temperatures are expected Tuesday with the potential for
strong to severe thunderstorms.
&&
.KEY MESSAGES...
As of 252 PM EDT Monday...
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.
&&
.DISCUSSION...
As of 252 PM EDT Monday...
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.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...VFR conditions will prevail through the
TAF period. SKC conditions this evening will see gradually
increasing clouds overnight, though expect ceilings to remain
AOA 10 kft through 12z Tue, and likely AOA 4000 ft through the
remainder of the TAF period. Isolated to scattered
showers/thunderstorms are possible Tuesday afternoon, 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.
Outlook...
Tuesday Night: VFR. Chance SHRA, Slight chance TSRA.
Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA.
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 300 AM EDT Monday...
A Lake Wind Advisory is in effect for the Broad Waters of Lake
Champlain. Winds have been slow to materialize thus far after
plenty of cloud cover and rainfall this morning stunted the
winds on Lake Champlain. Winds have currently increased to 15
knots in the broad lake and will continue to increase to 25
knots between 8 and 10 PM this evening. These stronger winds
will continue through 8 AM on Tuesday and will diminish to 15
knots or less on Tuesday. Waves are currently ranging between 1
and 2 feet and are expected to increase to 2-4 feet this evening
with the highest waves expected across the broad lake.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Clay
DISCUSSION...Neiles/Clay
AVIATION...Hastings
MARINE...Clay
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