933
FXUS61 KALY 181809
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
209 PM EDT Tue Aug 18 2026

.WHAT HAS CHANGED...
Patchy to localized areas of radiational fog was slightly
expanded further across eastern NY and western New England
tonight with ridging building in briefly. Some patchy fog was
also added for portions of of region Wed night-Thu morning.

A slight chance of showers was expanded further northward to
southern VT, the Berkshires, Taconics, southeastern Capital Region
and the eastern Catskills for Thu afternoon with the slower movement
of the cold front.

&&

.KEY MESSAGES...
1) Isolated to scattered showers, with isolated thunderstorms,
are expected Wednesday afternoon into Thursday, as a cold front
slowly moves southward across the region.

2) Unsettled weather returns over the weekend, as a broad upper
level trough impacts the region, although there is low
confidence in the timing, rainfall amounts and details with this
system.

&&

.DISCUSSION...
KEY MESSAGE 1...

High pressure builds in briefly tonight into early Wednesday
with patchy to localized areas of radiational mist or fog
occurring across the region, especially in the sheltered
valleys, as temps fall off into the 50s to around 60F with a
few upper 40s over the southwest Adirondacks. The mist or fog
burns off quickly with mid and high clouds increasing ahead of a
pre-frontal sfc trough and a cold front approaching from the
Great Lakes Region and southeast Canada. The best chance of
showers and isolated thunderstorms will be west/northwest of
the Greater Capital Region. The latest HREFs indicates mean
SBCAPE of 250-750 J/kg with 0-6 km shear 30-40 KT. Some of the
CAMs like the 3-km NAM have SBCAPEs around 1000 J/kg or so with
higher dewpts. The instability being limited showed keep
updrafts from being tall enough for any severe threat. Some
gusty winds may occur with a few storms...and the showers
weaken, as they move towards the Capital District and Hudson
Valley by nightfall. Max temps rise into the lower to mid 80s in
the valleys and upper to 70s over the hills and mtns.

The pre-frontal trough moves through at night with the showers
weakening, as they move eastward with limited upper level
support and moisture convergence. The cold front will be moving
across the southern half of the forecast area in the late
morning through the afternoon. Some patchy fog may occur
especially north and west of the Albany in the morning. The
latest NBM had very little PoPs north of the mid-Hudson Valley.
We collaborated with WFOs GYX/BTV/BOX and expanded the slight
chance of showers to southern VT, the southeast Capital Region
and Berkshires and points south. If the front is faster, then
the showers and isolated thunderstorms will be south of the Mass
Pike and closer to I-84. Once again, instability looks limited
with SBCAPEs mainly 750 J/kg or less near I-84 in southern
Dutchess and Litchfield Counties, so thunderstorms are expected
to be non-severe. High pressure builds in Thu night thru Friday
with cooler and drier weather.

KEY MESSAGE 2...

The next chance of a widespread rainfall looks to be late
Saturday into Sunday. Mid and upper-level height falls occur
over the Great Lakes Region, southeast Canada into the
Northeast, as a deep upper trough develops based on the medium
range deterministic, AI and ensemble guidance. A series of
short-waves dig into the trough, as it amplifies and may close
off somewhere near NY and New England Sun into Mon. It may be as
far poleward as near James Bay. A southern stream disturbance or
sfc low may form near the Mid Atlantic Coast with the
developing upper-level trough Sat night into Sunday bringing
periods of rainfall with a few thunderstorms. The latest 13Z/NBM
indicates the probabilities >0.50" of rainfall for the 24-hr
period ending 8 pm Sunday are 40-70% across eastern NY and
western New England. The probs for >1.00" of rainfall are only
20-40%. The placement of the closed low and the amount of QPF
are still somewhat uncertain, but some locally heavy rainfall
may occur Sun-Mon.  We will continue to monitor guidance trends
throughout the week. Temps trend cooler than normal for the 2nd
half of the weekend into early next week. A break in the pcpn
may occur Mon night into Tue, as the upper low moves down
stream.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Through 18Z Wednesday...VFR conditions will prevail for the
majority of this TAF period across all terminals, with variable
to light northwesterly winds persisting throughout this
afternoon. The consistent MVFR cigs across the region this
morning has finally begun to burn off, with some lingering low-
to-mid level clouds expected to stick around through this
evening. Winds will gradually weaken and become calm after 00Z,
which will persist throughout the overnight hours at all
terminals. Given the calm winds and mostly clear skies, there is
potential for the development of radiational mist/fog after
06Z. There is higher confidence for this to occur at KGFL and
KPSF, which could see brief drops to IFR vis, while there is
lower confidence for KALB and KPOU, reflected by TEMPO groups
with brief drops to MVFR vis. Any mist/fog that does develop
should burn off by 12Z Wednesday, leaving VFR conditions and
light southerly to southwesterly winds through the rest of the
TAF period.

Outlook...

Wednesday Night: No Operational Impact. Patchy FG.
Thursday: Low Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: Low Operational Impact. Slight Chance of SHRA.
Saturday Night: Moderate Operational Impact. Likely SHRA.
Sunday: High Operational Impact. Definite SHRA...TSRA.

&&

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

&&

$$

DISCUSSION...15
AVIATION...23