175
FXUS61 KBTV 120634
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
234 AM EDT Tue May 12 2026
.WHAT HAS CHANGED...
As of 232 AM EDT Tuesday...
Little changes made to the going forecast. Dry, cool weather is
on track to trend wetter.
&&
.KEY MESSAGES...
As of 232 AM EDT Tuesday...
1. Cool and frosty this morning with low relative humidity in
the afternoons through midday Wednesday.
2. Widespread, beneficial rainfall expected by midday Wednesday
and remaining active through the late week.
3. Seasonably warm temperatures are expected for the weekend
into early next week, with a few chances for showers possible.
&&
.DISCUSSION...
As of 232 AM EDT Tuesday...
KEY MESSAGE 1: Temperatures this morning are widely variable. A subtle
upper trough has managed to produce a few sprinkles and clouds,
especially along the international border. So temperatures range
from the upper 20s to mid 40s. We`ll trend towards fair weather
cumulus during the day with very dry air in place. Northwest flow
will keep conditions cool across the region, but abundant sunshine
should push temperatures into the 50s to near 60 at least. 850mb
dewpoints will be around -5 to -7 C, and should mix to the surface
by afternoon. Surface dewpoints will likely be close to yesterday`s
observed values down to the low to mid 20s. This will result in
minimum relative humidity values around 25 to 35 percent this
afternoon. Fortunately, winds will be relatively relaxed today, with
5 to 10 mph northwesterly winds and a few gusts around 15 mph.
Overnight, the next approaching system will start to spread some
clouds eastwards. So northern New York will observe greater cloud
cover for tonight than Vermont. Most of the frost potential will
reside in the Northeast Kingdom, which has yet to enter their
thermally defined growing season. Still it`ll be plenty cool with
near freezing temperatures to around 40 F.
KEY MESSAGE 2: An upper trough will close off into an upper low and
slowly amble southeastwards. There are some timing differences with
the arrival of precipitation. Some have precipitation arriving
fairly early in the day Wednesday, while some wait until afternoon.
The NBM forecast follows a fairly typical middle road given it is a
blend. It may be entirely based on saturation, as the initial wave
of precipitation may fall as virga for a time given the dry air mass
being replaced. Nevertheless, by late morning and early afternoon, a
solid shield of precipitation will translate northeastwards. By
evening, our forecast area will be in the warm sector as the stacked
system matures. Some instability on the order of 150-350 J/kg will
develop over northern New York, and this could produce a narrow
strip of convection with a rumble or two of thunder not out of the
question, mainly towards St. Lawrence and Franklin Counties of New
York.
By nightfall on Wednesday, the surface low loses steam and the loss
of daytime heating results in a collapse of the frontal boundary.
However, the upper low will continue to intensify. A secondary low
will attempt developing near Long Island, but another low will also
track near or just east of the 40 N, 70 W benchmark, and the coastal
low will probably absorb the secondary low. Upper level
southeasterly flow will develop as the upper low intensifies and
shifts to our southwest over western New York. So moisture will get
advected back over our region, in particular across Vermont during
the day Thursday. The coastal low will amble towards the Gulf of
Maine as the upper low passes south, and moisture wrapped up in the
upper level feature will likely keep precipitation going into
Friday. However, another system will approach from the west and act
as an escort for this slow moving upper low. Rainfall amounts
between Wednesday and Thursday will generally be a needed 0.50-
1.25", locally up to 1.50" possible.
KEY MESSAGE 3: Heading into the weekend, low pressure looks to
shift out of the region towards the Canadian Maritimes, with
high pressure trying to nose into the region. Some drier weather
is expected in comparison to the mid-week system, although some
showers will be possible as a shortwave disturbance looks to
move through the region. As of now, it looks like precipitation
this weekend into early next week will be more showery, with no
day looking like a complete washout, but trends will need to be
monitored as we get closer as there is still plenty of
uncertainty. Temperatures look to be near or above seasonal
normals for this time of year, with daytime highs in the 70s and
overnight lows in the 40s to mid 50s as we head into next week,
with some locations in southern Vermont possibly nearing 80
depending on precipitation and how much warming is able to take
place.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Through 06Z Wednesday...Currently VFR conditions at all terminals,
which is expected to persist through the forecast period. Calm winds
and clearing skies continue overnight tonight. Given these
conditions, there is the potential for localized stratus and fog to
develop towards dawn at KSLK, but based on model soundings and low-
level moisture there is low confidence. Winds will pick up again
after sunrise, and primarily be south/southwesterly. Gusts are
likely at KMSS/KSLK from 15z onward and KBTV from 20z onward as
the cold front approaches.
Outlook...
Wednesday: MVFR. Definite RA.
Wednesday Night: Mainly MVFR, with local IFR possible. Definite
SHRA.
Thursday: Mainly MVFR, with local IFR possible. Definite RA,
Slight chance TSRA.
Thursday Night: Mainly MVFR, with local IFR possible. Likely
SHRA.
Friday: Mainly MVFR, with local IFR possible. Chance SHRA.
Friday Night: MVFR/IFR conditions possible. Slight chance SHRA.
Saturday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Freeze Warning until 9 AM EDT this morning for VTZ006-008-010-
011-016>021.
Frost Advisory until 9 AM EDT this morning for VTZ002-005-009.
NY...Freeze Warning until 9 AM EDT this morning for NYZ026-027-087.
Frost Advisory until 9 AM EDT this morning for NYZ028-035.
&&
$$
WHAT HAS CHANGED...Haynes
DISCUSSION...Kremer/Haynes
AVIATION...Kremer
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