Mad River Glen

000
FXUS61 KALY 221812
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
212 PM EDT Sat Aug 22 2026

.WHAT HAS CHANGED...
Refined timing for showers and thunderstorms Sunday. First, 
more widespread round moves through in the morning to early 
afternoon. Additional, scattered showers and thunderstorms 
develop from mid afternoon to early evening. Coverage looks less
later in the day. There remains a Marginal Risk (level 1 of 5) 
of severe thunderstorms across the entire region on Sunday.

&&

.KEY MESSAGES...
1) Likelihood of showers and thunderstorms increases late 
tonight into Sunday. A few storms may become severe on Sunday.

2) Isolated to scattered showers and thunderstorms are expected
Monday and Tuesday, especially near and north of I-90. 
Temperatures will be below normal.

3) Chances of showers and thunderstorms return late next week
along with warmer temperatures.

&&

.DISCUSSION...
KEY MESSAGE 1...

An upper level trough over our region will deepen through the 
rest of the weekend, as a closed low develops across the Great 
Lakes and far SE Canada. Initially, our area will be on the 
downstream/diffluent side of the trough axis, with an associated
occluded surface front tracking NE Sun morning into early 
afternoon. A weak surface wave developing along the front along
with PWAT anomalies briefly increasing to +1 to +2 STDEV, could
result in brief downpours associated with any convection with 
the occluded front. There is a Marginal Risk (level 1 of 5) of 
severe storms Sunday, first with convective clusters/lines in 
the morning to early afternoon with potential for isolated 
damaging winds gusts. Then, there looks to be another period for
more cellular storm mode in the afternoon, with de-stabilization
(SB CAPE of 700-1500 J/Kg) and 0-6 km shear increasing to 35-40
kt in wake of the front (from REFS). Breaks of sunshine and 
residual low level moisture, along with falling heights aloft 
will result in potential for some additional severe storms, with
both isolated damaging wind gusts and large hail the main 
threats. Coverage of shower/T-storms should be less compared to 
the morning though.

Convection should dissipate shortly after sunset Sunday 
evening, as instability wanes and a small low level ridge builds
in from the west. 

KEY MESSAGE 2...

The main core of the upper level low mentioned above will be 
firmly established near the far southern Ontario/Quebec border 
by Mon and will be anomalously strong (500 mb height anomalies 
of -2 to -3 STDEV). A potent short wave disturbance rotating 
around the periphery of the low center, is expected to move 
across our area. This will result in additional showers and a 
few T-storms, especially Mon afternoon to early evening. Showers
will be most numerous across the Adirondacks, where there will 
be upslope/lake enhancement with a cold core aloft moving 
overhead with W-SW flow developing. While the overall threat for
severe weather appears low, there is potential for at least a 
few storms to produce small hail and/or gusty winds due to 
steepening low/mid level lapse rates. 

The core of the upper low is expected to track into southern 
Quebec on Tue, with the system's upper trough axis still in 
place across our region. This will result in additional showers 
developing, although lower coverage compared to Mon (mainly 
isolated to scattered). Showers will be most favored across 
westerly upslope areas of the higher terrain. It will also be 
breezy, with westerly winds gusting 20-25 mph at times in 
favored areas. Temperatures will remain below normal through 
Tuesday.

KEY MESSAGE 3...

After a break in the unsettled weather on Wed, chances for 
showers/T-storms will increase again during the Thu/Fri time 
frame, as a broad upper level trough approaches from the west. 
Potential multiple short wave passages should result in 
scattered to numerous showers, with T-storms also possible 
depending on instability and moisture return. Confidence in 
timing/coverage is low due to uncertainty in details of smaller 
scale features this far out. Temperatures look to warm back to 
normal mid-late next week too.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Through 18z/Sunday...VFR conditions remain through the afternoon 
across the terminals before ceilings begin to lower to MVFR this 
evening due to an approaching frontal system. MVFR ceilings will 
continue overnight at all of the terminals along with the 
possibility of fog/mist developing at KGFL and KPSF near sunrise. 
CAMs also suggest rain showers arriving between about 08z to 13z 
from the west lowering ceilings and visibilities to MVFR. After 
sunrise, model soundings continue to show low stratus persisting 
into the late morning maintaining MVFR ceilings and even lowering to 
IFR/LIFR for periods through the end of the TAF period. Additional 
chances of steadier rain showers and isolated thunderstorms through 
the end of the TAF period could lower flight conditions to MVFR/IFR, 
but confidence will increase with following TAF cycles. Winds 
through the TAF period will prevail out of the southeast with speeds 
this afternoon 5-10 kt becoming 5 kt or less overnight. Winds 
tomorrow generally range 5-10 kt, however stronger gusts around 25 
kt could accompany any thunderstorms that develops. 

Outlook...

Sunday Night: Low Operational Impact. Slight Chance of SHRA...FG.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Low Operational Impact. Breezy. Slight Chance of SHRA...TSRA.
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...07
AVIATION...53