184
FXUS61 KBTV 271751
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
151 PM EDT Fri Sep 27 2024

.SYNOPSIS...
Dry weather will prevail into the start of next week with
temperatures a bit above climatological normals. Fog development is
likely overnight in the typical valleys. The next chance of rain is
mid-week as a cold front moves through. Overall, it will be a
pleasant stretch of fall weather.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 145 PM EDT Friday...Fog is over for the day with mostly
clear skies prevailing. Expect more fog overnight into Saturday
morning.

Previous Discussion...Fog has continued to expand this morning
except across parts of the Northeast Kingdom where some mid-
level clouds have moved in from Canada. The low stratus deck in
the Champlain Valley has prevented temperatures from dropping as
low as expected so had to raise temperatures there slightly.
High pressure is building in and has pushed the rest of the high
clouds associated with yesterday`s low south of the region.
They should stay there through the day today. Overall, the
forecast is in good shape and few edits were made.

Previous Forecast...Extensive fog and low stratus have
developed overnight. On top of being fog season, they were
helped by yeaterday`s rain and a lack of boundary layer wind to
scour out the moisture. The fog and stratus have developed
across the climatologically favored valleys and also in other
areas like much of the Champlain Valley. Winds aloft will only
decrease as the night goes on and skies should remain mostly
clear, so they should continue to develop and spread.
Temperatures have been steadily dropping but the development of
the fog and stratus has slowed the rate of decrease a little.
Temperatures should still fall a couple more degrees by daybreak
though. The upper level trough will continue to move out to the
east today and ridging will build in. Surface high pressure
will remain centered over eastern Canada and it will keep the
remnants of Helene well to the southwest. Helene`s only impacts
could be a few very thin high clouds. Sunny skies and a
relatively warm airmass for the time of year will allow
temperatures to rise into the upper 60s and mid 70s today. Clear
skies and calm winds tonight will allow for another night of
efficient radiational cooling. Fog will at least develop in the
climatologically favored valleys, but whether it spreads outside
of there areas remains to be seen as it will be a day removed
from rainfall. Temperatures will fall into the 40s and low 50s.
Saturday looks to be almost a copy of today, though temperatures
will rise a couple degrees higher.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 344 AM EDT Friday...Little change in guidance this cycle with
regards to large scale synoptic pattern which features building
mid/upper lvl ridge over the northern Great Lakes into southern
Canada, while remnants of Helene slowly weaken over the TN/OH
Valleys. Using the progged IR satl feature from the GFS indicates
intervals of high clouds are likely from time to time during this
period. In addition, have noted both GFS/NAM soundings show
additional lobes of moisture btwn 850mb and 700mb on Sat Night,
which may limit areal coverage of fog. Otherwise, a 1020mb high pres
nosing into our northern cwa, wl keep moisture associated with the
remnants of Helene to our south and west thru the short term. Modest
low level waa continues on Sunday into Monday, with progged 925mb
temps btwn 16-18C, supporting highs well into the 70s on Sunday.
Lows mainly in the 50s, with some cooler 40s in deeper mtn valleys
likely.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 344 AM EDT Friday...Overall a very quiet with minimal
impactful/hazardous wx for the next 4 to 7 days. Still have 50 to
60% pops for weak frontal passage on Tues night into Weds. As this
system becomes closer in time, we should be able to narrow timing of
precip to a 3 to 6 hour window from west to east acrs our cwa. GFS
is very progressive with moving boundary acrs our fa, while ECMWF
tries to advect lingering moisture from mid/upper lvl cyclonic
circulation over the Ohio Valley into our cwa on Tues into Weds.
This would produce a longer duration of precip, with some slightly
higher qpf amounts. PW values range btwn 1.2 and 1.4" on Tues/Weds
ahead of boundary with favorable jet structure at 250mb for
promoting large scale synoptic ascent. If these ingredients combined
with low level convergence along boundary continue to be present
with upcoming system, pops wl need to be increased. In addition,
still some uncertainty on timing, but once our guidance fine tunes
the timing, confidence wl increase, resulting in some higher pops in
the categorical (80-90%) range late Tues into Weds time frame. Llvl
caa behind this boundary is modest, so most of the cooler temps wl
be driven by the increasing clouds/precip on Tues/Weds, with temps
mostly in the 60s. However, southerly flow ahead of this wl help
advect much above normal temps into our cwa on Sunday/Monday with
highs well into the 70s to near 80F. Lows generally in the upper 40s
to upper 50s, cool back into the upper 30s to upper 40s by Weds and
Thurs nights.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Through 18Z Saturday...VFR conditions will prevail through the
day with few-sct 035-050 fair weather cumulus for the afternoon.
Another round of fog is expected overnight with a mix of
conditions expected. Best chances for IFR/LIFR are SLK/EFK/MPV,
but can`t rule out some IFR/MVFR for BTV/PBG/MSS. Model winds
are suggesting light northeasterly flow off the Winooski which
would favor fog advection towards the terminal. RUT could
briefly see some fog 01-04Z before drainage winds increase to
mix fog out; otherwise, RUT will be VFR. Winds will remain light
with a slight northeasterly flow for Saturday in general.

Outlook...

Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Slight chance SHRA.
Tuesday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Wednesday: Mainly MVFR, with areas VFR possible. Chance SHRA.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Myskowski
NEAR TERM...Boyd/Myskowski
SHORT TERM...Taber
LONG TERM...Taber
AVIATION...Boyd