Summit, Vermont Weather Forecast Discussion

818
FXUS61 KBTV 091200
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
800 AM EDT Tue Sep 9 2025
.SYNOPSIS...
Prolonged dry conditions are expected with high pressure in place
through mid week characterized by pleasant afternoon temperatures
and morning fog for river valleys. Patchy frost this morning, and
potentially again late this week for Adirondack and northeastern
Vermont communities, will be the primary weather concerns. A dry
cold front will move through Thursday bringing northerly breezes and
possibly enhancing fire weather concerns given dry vegetation. The
next chances of widespread rain will hold off until late weekend
into the beginning of next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 759 AM EDT Tuesday...Issued a quick update to expire the
Frost Advisory. Temperatures are still in the low to mid 30s in
the Adirondacks and Northeast Kingdom, but things should warm
steadily as the sun rises.
Previous discussion...Temperatures are cooling as expected
in the Adirondacks and northeastern Vermont supporting the high
likelihood of frost formation. Otherwise, high pressure will
persist with slowly modifying temperatures warming through
Wednesday. Frosty lows this morning in the 30s for the
Adirondacks/northeastern Vermont and 40s elsewhere will warm
into the low/mid 70s this afternoon. Tonight, temperatures cool
again, but lows will be favored to be marginally warmer(upper
30s and 40s). As such, frost chances will be more confined to
coldest hollows. Along Lake Champlain, temperatures should be
warmer, around 50 degrees, as a weak low level jet traverses the
Champlain Valley. Relatively warm lake temperatures will
support better mixing allowing for some breezes of 10 to 15 mph
to surface disrupting radiational cooling. Otherwise,
temperatures warm back into the 70s for Wednesday afternoon.
Morning fog will remain probable for river valleys.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
As of 227 AM EDT Tuesday...Pervasive dry conditions persist Wednesday
night and Thursday as a dry cold front approaches and moves through
the region. While not a strong front, there is enough thermal
packing and sufficient pressure gradient to support daytime
gusts of 15 to 25 mph, with the Champlain Valley and higher
terrains on the higher end of this range. This will have
implications on fire weather since the region is experiencing a
period of significant drought. Fine vegetation will be parched
on top of dry 100/1000hr fuels - last week`s rainfall had little
impact on slaking moisture needs for larger fuels. These
conditions warrant continued scrutiny since they point to
potential for higher rates of fire spread.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 258 AM EDT Tuesday...A push of somewhat stronger cold air
advection will be ongoing Thursday night before relaxing
overnight. How quickly these northerly winds die off will be
important for potential frost formation; generally while
forecast lows currently suggest potential for frost, a shallow
inversion will have to develop quickly enough before sunrise for
this to happen. Low temperatures from the deterministic NBM are
less cold and more reasonable than most of the probabilistic
NBM data, which has many members that are likely too cold given
the somewhat breezy pattern. Friday looks dry and sunny, but
with high pressure building back in from the north, winds will
be light but relative humidity during the afternoon will
approach 30%, especially in the Upper Valley. Probabilistic
data shows a range of 27-33% at 2 PM in Springfield, Vermont, as
an example. Breezier conditions by comparison are favored for
the weekend as chances for a frontal system to approach
increase, with winds southerly on Saturday and potentially
flipping from southerly to northerly on Sunday. Aside from
Thursday, Saturday currently looks like the next chance of
overlapping wind and low relative humidity concerns for fire
weather.
While the late weekend period is still likely to remain dry, chances
for showers has increased on Sunday, with a slightly higher
probability of rain in northern New York than in Vermont. This
difference may be tied to the wettest cluster of the most recent
complete run of the global ensembles, which features a partially
closed 500 millibar low over northern portions of the Great Lakes.
This feature would therefore be slow to move eastward, such that the
showers associated with this unsettled weather could mainly stay to
our north and west. That being said, other scenarios show the wave
opening up such that some light rain amounts could be more
widespread across our region, or the low is cutoff over western
portions of Ontario keeping us under a strong ridge with continued
fully dry conditions. Unsurprisingly, statistical confidence of both
high and low temperatures decreases quite a bit Sunday and Monday
compared to Saturday. Generally temperatures through the period will
remain near normal, but clouds and precipitation could make Sunday
and/or Monday a bit cooler in some areas if the wet scenario
occurs.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Through 12Z Wednesday...Dense valley fog in the favored
locations is beginning the process of dissipating, with it fully
out of the SLK area by 1230Z and MPV in the 1330-1400Z period.
Otherwise, skies in the airspace are clear and will remain that
way through most if not all of the period. Some clouds in the 5
to 7 thousand foot layer may approach from the south towards the
end of the TAF period such as RUT and MPV, with the latter site
still favored to see another round of radiation fog but with
greater uncertainty than last night. Southerly winds just off
the deck are expected to be present for all of the overnight
period, with flow possibly near 20 knots below about 1000 feet
agl at SLK greatly reducing dense fog potential. Surface winds
at most sites, aside from in the Champlain Valley, will return
to calm or terrain-driven and light towards 00Z following a
period of diurnally-driven light south winds from about 15Z to
22Z.
Outlook...
Wednesday: VFR. NO SIG WX.
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. NO SIG WX.
Saturday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Boyd
NEAR TERM...Boyd/Hastings
SHORT TERM...Boyd
LONG TERM...Kutikoff
AVIATION...Kutikoff

NWS BTV Office Area Forecast Discussion