218
FXUS61 KALY 200547
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
147 AM EDT Fri Sep 20 2024

.SYNOPSIS...
Patchy morning fog, then dry conditions for eastern New
York today and mostly to partly cloudy skies. For western New
England, chances of showers for Saturday morning before dry
conditions returns for the rest of this weekend through Tuesday.
Chances of showers increase Tuesday night into Wednesday with
unsettled weather conditions for mid week. Temperatures become
seasonable today and continues for next week, with a few locations
seeing cooler than normal temperatures.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 12:30 AM EDT...Nighttime microphysics satellite imagery
continues to show high cirrus clouds across the Mid-Hudson
Valley and across western New England. Valley fog can still
develop through this morning, especially for the Schoharie
Valley. The current forecast is doing well through this morning
so no changes were needed, see previous discussions below for
more details...

.UPDATE...No significant changes with this update. Temperatures
continue to cool into the 60s(lower elevations) and 50s(higher
elevations) with tranquil conditions late this evening.

.PREV DISCUSSION[0746]...Satellite imagery shows high level
cirrus clouds in place from around the Hudson Valley east, with
some thicker mid level clouds farther east into New England.
Some of these thicker clouds could eventually push westward into
western New England overnight, which may limit fog potential
there. Farther west across eastern NY patchy fog is more favored
with only thin cirrus clouds overhead. Rain-free conditions
will prevail again tonight.

While tranquility persists here, just off the New England
Coast, a coastal low pressure system has continued to organize
and deepen throughout the day as it slowly inches farther north
and slightly west. Being on the back side of this system, the
only true impacts that have been felt thus far as a result of it
have been the spreading of broken cirrus bands especially into
our New England zones. Of course, with subsidence juxtaposing
vertical motion, coverage has remained limited. However, through
tomorrow morning, clouds will gradually increase from east to
west as the aforementioned system tracks farther north and
retrogrades closer to the New England Coast. The most extensive
coverage will primarily lie to the east of the Hudson River
courtesy of upper ridging and surface high pressure remaining
nearby aiding to keep areas to the west mainly clear.
Radiational cooling will therefore aid in the development of
patchy fog for some sheltered and low-lying areas. Low
temperatures tonight will fall largely to the mid to upper 50s
across the region.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
The coastal low continues to spin just off the New England Coast
tomorrow, allowing clouds to continue to spread westward. Skies
are not anticipated to be completely obscured, however, as high
pressure and weak ridging in the Great Lakes continues to pose
counteracting subsidence. Therefore, coverage was maximized at
partly to mostly cloudy with less coverage to the west of the
Hudson and more to the east.

Additionally, throughout the day tomorrow, a side-door cold
front will gradually sink south towards the region from
southeast Quebec/northeast New England. Little additional
moisture than that which will be introduced from the cyclonic
flow of the adjacent low will accompany this front. And while
it will provide some additional forcing for ascent, little if
any precipitation is expected as a result of its southwestward
track into the region. It is possible that an isolated, light
shower or two develop in the Upper-Hudson Valley and/or Southern
Vermont tomorrow afternoon along its progression, however, with
forecast soundings showing fairly dry low-level conditions, its
possible that rain could evaporate before reaching the ground.
For now, excluded slight chance PoPs, though this could change
in coming updates. High temperatures tomorrow will be a few
degrees cooler than today with mid to upper 70s below 1000 ft
and upper 60s to low 70s both above and within much of our New
England counties courtesy of the anticipated, more extensive
cloud cover.

The aforementioned front continues to sink through the region
Friday night into Saturday morning, maintaining partly to mostly
cloudy skies overnight. As such, patchy fog will be highly
limited Friday night and lows will fall primarily to the low to
upper 50s. The aforementioned front will wash out throughout the
day Saturday, but with the coastal low still within reach, a
shortwave perturbation will rotate about its western periphery
and through the region, allowing for some scattered showers in
southern Vermont before daybreak. Additional showers are
possible east of the Hudson Saturday as the low sinks back south
and west, so maintained slight chance PoPs mainly for western
New England. A weak shortwave disturbance will also pass by to
our west throughout the day Saturday, but limited forcing should
keep showers at bay. Highs will be in the upper 60s to low 70s
with pockets of mid 70s possible in valley areas.

The coastal low will continue to track farther into the
Atlantic Saturday night, reinforcing widespread dry conditions
across the region in time for upper-level ridging to begin
approaching from the west. Low temperatures Saturday night will
fall to the low to upper 50s with pockets of upper 40s above
2000 ft.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Another stretch of dry weather is in store for at least the
first half of the long term forecast period with cooler
temperatures to accompany. Upper-level ridging begins to build
north and east from the Ohio Valley Sunday, becoming situated
across the region by Sunday night. Surface high pressure
extending south from Quebec will pair with ridging aloft to
ensure dry conditions through at least Monday. Highs Sunday will
range primarily from the upper 60s to low 70s before cooling to
the mid/upper 60s to low 70s with pockets of low 60s across
higher terrain Monday.

The remainder of the long term forecast period contains some
uncertainty as it pertains to a frontal system looking to
approach the region from the Great Lakes. Timing seems to be
the most significant difference amongst sources of guidance,
though the track of the low also remains somewhat uncertain at
this time. Some medium range models indicate the system`s impact
beginning as early as Tuesday morning where as others implicate
Tuesday night as the onset of showers. This system does,
however, look to be the next potential chance for more
widespread showers across the region Wednesday into Thursday.

High temperatures Tuesday through Thursday will be fairly
similar at mid/upper 60s to pockets of near or just above 70
with low 60s possible at higher elevations.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...

While VFR conditions begin this TAF period, expecting
deteriorating conditions through sunrise for the terminals
thanks to ongoing radiational cooling conditions and incoming
stratus from New England. Latest GOES16 night fog channel shows
a low stratus deck resulting in MVFR cigs tracking from west to
east through MA/CT and is already near the CT river valley.
Expecting low stratus to reach PSF by 07 - 09 UTC leading to
MVFR cigs with MVFR cigs continuing through 13-14 UTC. Some
intermittent MVFR vis is also possible from fog as seen in
upstream observations in New England so included that in the
TEMPO groups. However, we have higher confidence on reduced
flying conditions from lower ceilings than visibility at PSF.

Latest GOES16 night fog channel shows fog already developing in
the Hudson Valley but as thus far avoided the GFL, PSF and ALB.
With a zero dew point depressions at GFL, expecting fog to
develop within the next 1-2 hours resulting in IFR vis/cigs that
persist through 12-13 UTC. Less confident at ALB and POU where
dew point depressions remain 2-5 degrees and with the ENX VAD
wind profile showing breezy winds not far off the surface, it`s
possible that fog struggles to develop. However, given KMGJ has
already observed MVFR vis from fog, we have higher confidence
for MVF fog/cigs to develop at POU so included TEMPO group there
06 - 09 UTC before MVFR conditions prevail through 12-13 UTC.
Less confident in MVFR conditions at ALB given high dew point
depression but given latest satellite trends and continued
radiational cooling through sunrise, included a TEMPO for MVFR
conditions 09 - 12 UTC.

IFR/MVFR conditions early this morning should improve and return
to VFR at all terminals by 12-14 UTC. VFR conditions prevail
through the day with just some diurnally driven stratus clouds
at 4-6kft developing by 16 - 17 UTC as we reach out convective
temperature. Some isolated showers are not completely ruled out
this afternoon but given uncertainty on exact location, only
include VCSH at GFL and PSF. VFR conditions through 00 - 03 UTC
at all terminals but then MVFR stratus clouds look to redevelop
by or shortly after 03 UTC for POU, PSF and GFL.

Winds will be light and variable through sunrise. Then, winds
become east-northeast reaching 5-8 kt with gusts up to 15kts by
14 - 16 UTC at all terminals. Winds turn light and variable
by 23 - 01 UTC.

Outlook...

Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.
Monday Night: Low Operational Impact. Slight Chance of SHRA.
Tuesday: Low Operational Impact. Slight Chance of SHRA.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$

SYNOPSIS...Webb
NEAR TERM...Gant/JPV/Webb
SHORT TERM...Gant
LONG TERM...Gant
AVIATION...Speciale