Olympus, Vermont Weather Forecast Discussion

574
FXUS61 KBTV 051836
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
236 PM EDT Sun Oct 5 2025
.SYNOPSIS...
High pressure will remain in control of the weather through
tomorrow, providing mostly clear skies and temperatures climbing
well above normal. Some daily record highs have been broken today
and more are in jeopardy tomorrow, including the record high
temperature for the month of October in Burlington. A wetting
rainfall is expected Tuesday afternoon and night, followed by cool
and dry conditions returning for the latter half of the week.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 233 PM EDT Sunday...Daily records highs have been broken
already today, with temperatures expected to continue to climb this
afternoon. The October record high temperature of 86 for Burlington
is also in jeopardy, with a current temperature of 85. Humidity has
also been increasing a bit, with some sheltered locations seeing dew
points in the low sixties. It may be October, but these highs are
above the highest average highs in July. The center of the high
pressure continues to slide off to the east so stronger southerly
boundary layer flow will develop. While parts of the Connecticut
River Valley may decouple tonight and see fog, the winds should be
too strong elsewhere. A stronger southwesterly low level jet will
move into the region late in the day tomorrow. It will cause strong
channeled flow across the St. Lawrence Valley where gusts in the 20
to 30 percent range are expected. Relative humidities will also drop
to around 30 percent, so there are elevated fire weather concerns,
particularly across the St. Lawrence Valley. The strongest part of
the jet looks to move in tomorrow night, but inefficient mixing will
cause winds to decrease.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 233 PM EDT Sunday...A strong cold front moves through Tuesday
and Tuesday night, bringing a slow moving line of showers. An
isolated rumble of thunder is possible, but instability is quite
low. Ahead of the front, there will again be near critical fire
weather conditions, mostly across Vermont. The rain should move into
northern New York early enough to prevent the relative humidities
from dropping as far, but across Vermont, values in the 30 to 40
percent range are possible. Winds will be stronger regionwide, with
gusts in the 20 to 30 mph range expected. These will likely be
highest in the Champlain Valley due to channeled flow. The front
will provide welcome rain, with values above an inch possible in a
few areas. GEFS, EPS and CAN ensemble probabilities are currently
around 33 percent for most of the region, but models have been
trending wetter due to a slower passage, so these may come up a bit.
The one issue is that the strong southwesterly jet may downslope the
Champlain Valley and limit totals there. The airmass behind this
front will be much more seasonable.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 233 PM EDT Sunday...Brisk northerly winds bringing in much
cooler and drier air will be the main story for Wednesday. Showers
will likely be wrapping up in southern/eastern areas, with a sharp
clearing trend lagging only a short distance behind as abundant dry
air settles in. Little warming will occur as 850 millibar
temperatures steadily fall into the 10- 20th climatological
percentile, roughly at the freezing mark - as such, mountain summits
will be down right cold with wind chills as low as the 20s. Even
with superadiabatic lapse rates during the afternoon, this air mass
would lead to temperatures struggling to hit 60 degrees even in the
warmest spots, especially if timing of the cold air advection is
faster than consensus. The wind speeds won`t be particularly
impressive, reaching as high as the 75th percentile at 925 millibars
early in the day, particularly across central Vermont, corresponding
to values near 25 MPH. However, impressive lapse rates with
unidirectional northwest flow should allow spots downwind of the
Green Mountain higher peaks to see efficient mixing with sneaky
impacts due to leaf fall and wet conditions from the rain early in
the day.
Probability of freezing temperatures overnight/early Thursday
remains high (at least 60%) in much of the St. Lawrence Valley and
pockets of central and eastern Vermont. Depending on how quickly
winds calm in these areas, temperatures could fall well below
freezing. With the core of the high pressure area moving into the
area on Thursday, the stage will be set for the coldest night of the
season Thursday night when sub-freezing temperatures will be
widespread away from the proximity of Lake Champlain. The ECMWF
Extreme Forecast Index even suggests unusually low temperatures
Friday morning, most substantially so across northeastern Vermont
where current forecast lows in the mid 20s might not be cool enough.
Thereafter, it still looks like a moderating trend towards normal
temperatures will occur. Signals for any significant weather Friday
through the weekend are non-existant. Did note that the spread in
high temperatures on Sunday is substantially higher than previous
days, which is probably due to a couple of scenarios evident in 500
millibar heights that either show troughing/cooler conditions or
strong ridging/warmer conditions. However, as of now the dominant,
consensus idea is for broad ridging centered to our north, keeping
us seasonably warm and dry as temperatures trend slightly warmer
from day to day.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
High pressure will continue to dominate with only modest
south/southwesterly wind fields. Some diurnally-driven, mechanical
mixing will cause some gusts to near 20 knots before diminishing
after 22-00Z, with resumption of similar conditions 13Z onward. Late
in the period wind gusts near 25 knots are probable at MSS.
With regards to fog potential, think it is diminished compared to
last night due to southwesterly winds off the deck. As such, no TAF
shows IFR conditions although at SLK or MPV it cannot be ruled out
in brief intervals overnight as these sites will decouple with
temperatures likely dropping below crossover temperatures again in
the mid 50s.
Outlook...
Monday Night: VFR. NO SIG WX.
Tuesday: Mainly VFR, with local IFR possible. Definite SHRA,
Slight chance TSRA.
Tuesday Night: MVFR/IFR conditions possible. Definite SHRA.
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.
&&
.CLIMATE...
The heat will persist through Monday and many records are in
jeopardy. The most likely dates for records will be Sunday
October 5th and Monday October 6th. Below are some of the daily
records in jeopardy of being broken (current forecast at or
within 3 degrees of the record).
Record High Temperatures:
October 5:
KBTV: 83/2023 BROKEN
KMPV: 82/1951
KPBG: 80/2005
KMSS: 85/1991
KSLK: 83/2023
October 6:
KBTV: 82/1990
KMPV: 79/1990
KMSS: 81/2005
KSLK: 80/1946
Record High Minimum Temperatures:
October 5:
KPBG: 56/1973
October 6:
KBTV: 64/1937
October 7:
KBTV: 62/1947
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Myskowski
NEAR TERM...Myskowski
SHORT TERM...Myskowski
LONG TERM...Kutikoff
AVIATION...Kutikoff
CLIMATE...BTV

NWS BTV Office Area Forecast Discussion