908
FXUS61 KALY 221205
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
805 AM EDT Sat Aug 22 2026

.WHAT HAS CHANGED...
SPC expanded the Marginal Risk for isolated severe weather
(level 1 of 5) on Sunday to now cover most of eastern NY and
western New England. WPC removed the marginal risk for excessive
rainfall (level 1 of 4) for Saturday.

&&

.KEY MESSAGES...
1) After a dry Saturday, areas of showers and thunderstorms
arrive late tonight into Sunday A.M with showers and storms
returning Sunday P.M. There is a marginal risk (level 1 of 5)
for isolated severe thunderstorms across much of eastern NY and
western New England Sunday P.M.

2) Isolated to scattered showers and thunderstorms continue Monday
and Tuesday, especially near and north of I-90, with temperatures
remaining slightly cooler than normal.

&&

.DISCUSSION...
KEY MESSAGE 1...

Broad troughing continues developing over the Upper Great Plains
into the Great Lakes today while the Northeast remains on the
west side of large scale ridging over the western Atlantic.
While height falls creep into western NY today, eastern NY and
western New England remains under the influence of weak
subsidence, keeping us dry. Tonight, our upstream trough over
the Great Lakes amplifies and digs into the Ohio Valley as two
shortwaves phase together with the parent cyclone taking on a
negative tilt. This results in strengthening upper level
diffluence over the mid-Atlantic as a warm front lifts northward
with a weak sfc low developing along the boundary. Meanwhile,
strengthening southwest flow aloft will also allow moisture to
advect into the Northeast with PWATs rising over 1.50". Chances
for showers and even a slight chance for thunderstorms increases
from southwest to northeast 06 - 12 UTC Sunday as the front
approaches. Guidance continues to hint that the weak sfc low
will aid in a more organized area of rain/embedded storms. As
mentioned in the previous discussion, the latest probabilistic
guidance from the HREF continues to show potential for moderate
to heavy rain late tonight into Sunday morning with a 50 - 75%
chance for over 0.50" of rain 09 to 15 UTC Sun and even a 25-50%
chance for over 1" of rain. However, our recent dry stretch
will likely limit flooding and WPC removed the marginal risk for
excessive rainfall.

After this initial A.M period of rain/storms, we should have a
brief break before an occluded front and stronger height
falls from the closed parent low over the eastern Great lakes
arrive. There remain uncertainties regarding how much
instability can develop. While there will be plenty of low-
level moisture, morning clouds may struggle to break for sun
during the small window before the occluded front arrives Sun
P.M. Even still, mid-level dry air and cooler temperatures aloft
wrap eastward as the parent cyclone matures, helping to steepen
lapse rates with forecast soundings showing "tall- skinny" CAPE
developing. Given the high humidity, even limited insolation
will contribute to sufficient instability and help generate low-
topped convection. While 0-6km shear is rather impressive
ranging 40-50kts, 0-3km shear only ranges 20-30kts. Should weak
instability keep convection low-topped, storms will not tap into
the stronger deep layer shear, decreasing the severe weather
potential. SPC expanded the marginal risk (level 1 of 5) for
isolated severe weather to now cover much of eastern NY and
western New England given persistent forcing ahead of the parent
cyclone; however, weak instability/shear are listed as reasons
will severe weather may be limited. Main concerns are damaging
winds from any severe weather with a linear storm mode favored
as shear vectors remain parallel to the boundary.

KEY MESSAGE 2...

The vertically stack closed low and associated cold pool in the
eastern Great Lakes slowly advances eastward Monday into Tuesday
supporting slightly cooler than normal temperatures and
continued moist cyclonic flow aloft. Coverage of showers and
even low- topped convection increases Monday afternoon,
especially near/north of I-90, as additional shortwaves rotate
around the base of the closed low. Given the cool pool aloft, it
likely will not take much upscale growth before lightning
occurs with even small hail possible from any taller storms. As
winds aloft becoming westerly, a weak lake effect signal looks
to develop downstream of Lake Ontario, supporting steadier
periods of rain directed into the western Adirondacks and Mohawk
Valley Monday P.M into Monday night. Unsettled conditions
continue into Tuesday with additional diurnally driven showers
again mainly near/north of I-90 but shower coverage should be
lower than Monday as the parent cyclone slowly exits into New
England.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Through 12z Sunday...VFR conditions will remain steady
throughout the morning, giving way to lowering ceilings which
will fall into the MVFR category by this afternoon and evening
courtesy of increasing low-level moisture. MVFR ceilings will
then persist into the overnight as a complex weather system
further encroaches on the region. POU could see some light rain
showers by the end of the period, so input a PROB30 from 09-12z
to account for that potential. Forecast soundings indicate that
PSF could see a lowered ceiling into the IFR category by the end
of the period, but confidence is not very high in that element
of the forecast. Winds throughout the period will prevail
largely out of the southeast at sustained speeds under 10 kt.

Outlook...

Sunday Night: No Operational Impact. NO SIG WX.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Low Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Moderate Operational Impact. Chance of SHRA...TSRA.

&&

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

&&

$$

DISCUSSION...24/31
AVIATION...12