486
FXUS61 KALY 171846
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
246 PM EDT Mon Aug 17 2026

.WHAT HAS CHANGED...
Patchy fog was expanded further across eastern NY and western New
England tonight in the moist air mass before the cold advection
increases in the wake of the occluded front late tonight.

Patchy radiational mist/fog was included across the sheltered
valleys Tue night/Wed morning.

Friday into the weekend looks potentially unsettled with a wave
moving along the boundary stalled south of the region
initially, as well as a deepening mid and upper level trough
over the Great Lakes Region into the Northeast with a closed low
that may bring periods of rain especially late in the weekend.

&&

.KEY MESSAGES...
1)Scattered showers and isolated to scattered non-severe
thunderstorms will move across the region this afternoon through
tonight ahead of the occluded front.

2) Another round of isolated to scattered showers, with isolated
thunderstorms, is expected Wed pm into Thu, as a cold front
slowly moves across the region.

3) Potentially, unsettled weather returns Fri into the weekend
as a broad mid and upper level trough settles in, although there
is low confidence in the timing, rainfall amounts and details
with this system.

&&

.DISCUSSION...

KEY MESSAGE 1...
A cold front associated with low pressure over southeast Quebec
is catching up to a warm front over central NY and PA early
this afternoon, as a secondary low moves across southeast New
England. A moist and humid air mass will briefly impact the
region with dewpoints in the 60s to lower 70s this afternoon.
An occluded front will bring some scattered showers and isolated
to scattered thunderstorms. PWATS have risen into the 1.5-2.0"
range across the forecast area based on the SPC RAP
Mesoanalysis, as the 12Z KALY sounding was 1.94". Low-level
stratus is slowly eroding to partly to mostly cloudy conditions
this afternoon. SBCAPE has had trouble developing from the
Hudson River Valley/I-87 eastward so far. SBCAPEs 500-1000 J/kg
have been materializing north and west over the southwest
Adirondacks. The latest HREFs has mean SBCAPES of 750-1250 J/kg
late this afternoon into this evening from southern VT, the
Capital Region, and the eastern Catskills south and east with
weak deep shear 15-25 KT. The best 0-6 km bulk shear 25-35 KT is
over the far northwest zones, where some showers and isolated
thunderstorms are developing over the western Adirondacks. The
lack of robust instability, deep shear over the majority the
forecast area, and weak lapse rates aloft should keep the
thunderstorms that form non-severe. Some gusty winds and brief
localized downpours could produce ponding of water with a few
storms.

The front will move across the region slowly tonight with the
abundant low-level moisture remaining in place, as widespread
patchy fog to localized areas of dense fog will likely form,
especially where rain occurs. Lows fall back into the mid 50s to
mid 60s with the coolest readings west of the Hudson River
Valley over the higher terrain. Some modest cold advection will
occur over the northwest zones late.

KEY MESSAGE 2...

A few lingering showers persist over southern VT in the
morning, as high pressure builds in across the region with
partly to mostly sunny conditions and seasonable temps. High
will be seasonable in the the 80-85F range in the valleys and
mainly 70s over the hills and mtns. A window of mostly clear
skies and light to calm winds will allow for some patchy
radiational valley mist/fog in the sheltered valleys, as lows
will be in the 50s around 60F. The frontal boundary approaches
for Wed with a slight to low chance of showers and thunderstorms
especially north and west of the Capital Region over the
western Dacks and west-central Mohawk Valley. Instability looks
weak or limited with west-southwest low to mid-level flow. The
front looks to weaken at night with the showers/thunderstorms
diminishing. Temps will run near or slightly above seasonal
normals with 70s to lower/mid 80s. The frontal boundary makes
slow progress across the region by Thu morning. The best chance
for isolated to scattered thunderstorms will be along and
southeast of southern VT, the Greater Capital Region, and the
eastern Catskills in the afternoon. A few thunderstorms could
become strong, if moderate instability increases, but that is
unclear at this this time with the medium range guidance/ensembles.

KEY MESSAGE 3...

Some uncertainty continues Fri into the weekend. Some of the
medium range guidance has a wave developing along the stalled
front to the south of the region over PA and NJ for some rain to
impact locations from the Capital Region south and east, while
the ECMWF and some ensembles keep it dry with high pressure
building in. Our latest forecast from WPC for Days 4-7 keeps it
dry outside a slight chance of showers closer to I-84 on Fri.
The deterministic, AI and ensemble guidance continues to forecast
a broad, deepening mid and upper level trough over southeast
Canada, the Great Lakes Region and the Northeast for the
upcoming weekend into early next week. The chances of showers
and few thunderstorms continue late Sat into Sun for the trough
and a potential closed low. Some locally heavy rain could occur
depending where the mid and upper level low track and any
surface cyclones, but timing, evolution details and the amount
of rainfall still look very uncertain at this time. We will
continue to closely monitor trends through the week, as this
storm system is still several days away. Temps trend slightly
cooler than normal.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
We start the TAF period with either low VFR or MVFR conditions
at all TAF sites. Through 18/00z, MVFR and low VFR ceilings
continue to fluctuate due to passing rain showers and low
stratus clouds. Between 17/20z and 18/00z, all TAF sites could
see a passing rain shower. Forecast confidence is low for a
thunderstorm this afternoon, with a vicinity thunderstorm the
most likely scenario for this timeframe. So with higher
confidence for rain shower activity, continued mentioned rain
showers in PROB30 groups through 18/00z. Then, low stratus and
patchy fog develop for the overnight hours as winds become calm
and conditions are favorable, especially any TAF site that sees
a rain shower today. Confidence is highest for KPSF to develop
fog which has been introduced for 18/06z through 18/13z with
LIFR/IFR conditions. KGFL could see some patchy fog for MVFR
conditions between 3z and 6z, but low ceilings due to low
stratus will likely persist after 6z through 12z. For KALB and
KPOU, IFR ceilings are likely in store after 6z through 10-12z
due to low ceilings.

Outlook...

Tuesday Night: No Operational Impact. Patchy FG.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Low Operational Impact. Slight Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: Low Operational Impact. Slight Chance of SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.

&&

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

&&

$$

DISCUSSION...15
AVIATION...05