582
FXUS61 KBTV 202327
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
727 PM EDT Wed May 20 2026
.WHAT HAS CHANGED...
As of 220 PM EDT Wednesday...
Confidence is increasing on the potential for strong radiational
cooling on Thursday night into Friday morning, and nighttime
lows have been adjusted to reflect the potential for frost in
the Adirondacks and central Vermont into the Northeast Kingdom.
Additionally, precipitation chances have been decreased for
Saturday based on the majority of model scenarios trending
slower.
&&
.KEY MESSAGES...
As of 220 PM EDT Wednesday...
1. Temperatures will trend below seasonal normals, and frost
will be possible outside the Champlain Valley, mainly on Thursday
night.
2. Dry conditions are expected with a trend to very low
relative humidity, but also slackening winds.
3. Shower chances to end the weekend and begin next week.
&&
.DISCUSSION...
As of 220 PM EDT Wednesday...
KEY MESSAGE 1: Our moisture starved, but strong cold front is shifting
southeastwards in piecemeal fashion. After one more day of warmth
and humidity with spotty showers now shifting south, we`ll
experience 50s to near 60 Thursday, and then 60s for the rest of
the region during the day. Very cool weather is expected,
tonight. North flow will bring a significantly cooler air mass
taking temperatures into the 30s across much of northern New
York and the Northeast Kingdom, but it will be in the 40s across
the Champlain Valley and south-central Vermont. It will be an
advective cold with a steady north to northwest wind overnight,
and that will likely keep frost limited.
Temperatures on Thursday night appear likely to tank. Very dry mid-
level conditions will be present beneath a 1030mb. Widespread
frost/freeze is expected in the Adirondacks and central
Vermont up into the Northeast Kingdom. The probabilities for
the Champlain and St. Lawrence Valley are a little lower, but
mid 30s may not even be out of the question, especially for
areas removed from the St. Lawrence River and Lake Champlain.
Some moderation takes place, and we`ll trend relatively close to
seasonal norms with decreasing chances for frost the remainder
of the week.
KEY MESSAGE 2: The incoming air mass will be quite dry. Dewpoints will
likely fall near to below freezing on Thursday. Even with the cool
temperatures, the 30-35 degree dewpoint depression will result in
afternoon relative humidity values of 30-40%, locally in the upper
20s. Steady northwest winds around 10-15 mph and gusts up to 20 mph
will be possible. We`ll be somewhat further removed from
precipitation across the region, especially southern Vermont, which
last saw the greatest rainfall from the 1-2" soaker from a week ago.
For Friday, the warmer temperatures will come with little change in
surface dewpoints. The strong 1030mb high will be right overhead,
and sunny skies with variable winds are expected. Relative humidity
values will likely be in the 20s over most of the region. Saturday
will also be dry, but recycled maritime air will add at least some
humidity back into the air 32-40% over Vermont, and 35-45% over
northern New York. Some precipitation will approach the area from
the southwest, but likely not until Saturday night or later as a
decaying warm front struggles against the strong surface high.
KEY MESSAGE 3: Surface high pressure centered over Quebec retreats to
the northeast on Sunday as a low attempts to gain entry into the
region. While the precipitation associated with it will become more
disorganized as it moves in, shower chances persist from Sunday
through Monday. By the end of Monday, the combined GEFS/EPS/CMCE
ensemble probability of receiving over 0.5 inches of rain ranges
between 50 to 75 percent, with the highest values farther southwest.
The probability of seeing an inch is between 25 to 50 percent. The
rain will mostly be showery and stratiform and will not present a
flood threat. Uncertainty remains on how far north the precipitation
makes it, but under any situation, the days will not feature
consistent rainfall. Mostly dry weather should prevail toward mid
week, though a few chances of showers will continue.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...Brisk northwest winds 5 to 15 knots with
localized gusts up to 20 knots will cause areas of turbulence
near trrn this evening, before slowly weakening. Otherwise, VFR
conditions are expected to prevail for the next 12 to 24 hours
at all 7 of our TAF sites. A few gusts 15 to 20 knots are
possible again on Thursday between 15-21z.
Outlook...
Thursday Night: VFR. Patchy frost.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Chance SHRA.
Sunday: Mainly VFR, with local MVFR possible. Chance SHRA.
Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Memorial Day: MVFR. Chance SHRA.
&&
.MARINE...
As of 220 PM EDT Wednesday...
After a quick burst of gusts from the switch to northwest to north
winds on Lake Champlain having taken place, steady 10-20 knot winds
are expected for the afternoon. By evening, winds will likely
increase over Lake Champlain again, especially around midnight
before tapering off again tomorrow morning. Waves overnight
could build to 2-4 feet over the broad waters south of
Colchester Reef, and mostly 1-2 feet elsewhere.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Haynes
DISCUSSION...Haynes/Myskowski
AVIATION...Taber
MARINE...Haynes
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