970
FXUS61 KALY 311046
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
646 AM EDT Mon Aug 31 2026

.WHAT HAS CHANGED...
Continued trend to slow down PoPs with the showers this
afternoon with only slight or low chances along and west of the
Hudson River Valley prior to sunset.

Lowered max temps on Tue about 3-4 degrees below the NBM
blending with with NBM and MAVMOS guidance with back door cold
front and clouds through the day. Lowered PoPs into chance
category for showers/slight chance of thunderstorms for Tue-Tue
early evening with a brief break with short-waves with any
Marginal severe threat south and west of the Capital Region.

Unsettled pattern continues through the mid week with additional
chances for strong storms possible Wed-Thu with heavy rainfall
and at least isolated flash flooding, although there remains
some uncertainty in exactly how things will evolve this week
with the frontal boundary location.

&&

.KEY MESSAGES...
1) A low pressure system and a warm front brings showers and non-
severe thunderstorms tonight into early Tue with locally heavy
rainfall.

2) A few strong to severe thunderstorms south and west of the
Capital Region Tue afternoon into the evening with an isolated
flash flood threat for the region.

3) Additional rounds of showers and thunderstorms through the
mid week with potentially some strong thunderstorms on Wed with
isolated to scattered instances of heavy rainfall/ flash
flooding possible due to a stalled frontal boundary.

&&

.DISCUSSION...
KEY MESSAGE 1...High pressure builds in from southwest Quebec
with some patchy fog and stratus this morning that will burn off
in the late morning. The mid and upper level flow will be west
to northwest the next several days, as upstream ridging sets up
over the Upper Midwest, Great Lakes Region and Ontario with a
strong closed H500 anticyclone centered over the Lower MS and TN
Valleys. The cold front from this morning will slowly lift back
to north/northeast from PA/NJ and western NY with increasing
clouds and showers building in from the west/southwest in the
mid to late afternoon. We slowed down the PoPs/showers based on
the latest short-range guidance and CAMS. Temps will be
seasonable today with upper 60s to upper 70s across the region
with moderate humidity levels with dewpoints in the upper 50s to
mid 70s.

Tonight, the isentropic lift increases ahead of the warm front
and a short-wave rolls across the ridge into upstate NY. A wave
of low pressure or decaying MCS rides along the boundary
bringing periods of showers and some thunderstorms due to
elevated instability /Showalter stability indices below 0/ ahead
of the front and wave. Latest HREF guidance indicates mean
MUCAPEs generally 500 J/kg or less with 0-6 km shear 35-40 KT.
With the parcels elevated we are not expecting severe
thunderstorms. Rainfall could become moderate to locally heavy
with PWATs rising into the 1.5-2.0" range about 1 to 2 STDEVs
above normal. The CAMs have shifted slightly further south with
the coverage of the showers and thunderstorms with the most
widespread coverage from the Mohawk Valley/Capital Region
southward, but slight variations may occur. Ponding of water on
roadways may occur in a few spots. Gridded FFG values remain
high right now with drier weather recently. WPC maintains a
Marginal Risk (Level 1 of 4) in their Day 1 ERO. An isolated
flash flood threat can not be ruled out in case any training
occurs, but that looks low on the onset. The rainfall should
diminish Tue morning from west to east. Low temps will be
muggier in the mid 50s to lower 60s.

KEY MESSAGE 2...SPC has maintained a Marginal Risk (Level 1 of
5) for severe t-storms for locations south and west of the
Greater Capital Region/Berkshires. The areas highlighted are
the eastern Catskills, mid Hudson Valley, southern Taconics and
NW CT as well as the western Mohawk Valley of southern Herkimer
County. It is a tricky forecast to see where the warm
front/boundary sets-up, as some of the guidance like the GFS/NAM
show the boundary stalling south of the Capital Region with the
front acting like a backdoor cold front, as sfc ridging builds
back in from southeast Quebec and northern New England. The
forecast area could be caught in clouds most of the day with
north/northeast winds especially from the I-90 corridor north.
However, the latest HREF guidance does show the best 0-6 km deep
shear of 40-45 KT with mean SBCAPEs of 1000-1500 J/kg overlay
for the south/southwest zones in the Marginal Risk. Mid level
lapse rates look decent towards I-84. Some deep organized
convection could form with some diurnal heating on the warm side
of the boundary or outflow boundaries with strong to severe
thunderstorms with damaging winds and large hail, as well as
locally heavy rainfall due to the above normal PWATS. The severe
threat looks to be in the mid afternoon into early evening. We
kept PoPs in the chance to low likely range (35-60%) prior to
midnight.

Another ridge roller disturbance looks to arrive for Wed with a
more robust heavy rain/flash flood threat and additional strong
to severe thunderstorms. Nonetheless, WPC maintains a Marginal
Risk in the Day 2 ERO for Tue-Tue night across the forecast
area. Max temps were lowered some on Tue below the NBM with the
clouds and back door front likely south of Albany. We leaned
closer to an NBM/MAVMOS blend. We did not go as cool as the
METMOS values. Highs in the mid 60s to mid 70s will be common
from the Capital Region north and 70s to around 80F south.

KEY MESSAGE  3...A strong short-wave in the west/northwest flow
around the rim of the ridge arrives for WED. The frontal
boundary attempts to lift back to north/northeast across the
region. The 0-6 km shear is strong, but the instability looks
elevated initially. However, if we break into a warm sector some
strong to severe convection could form with the MCS/wave with
moderate to large instability. The threat for strong storms
looks like it would be greatest from the Capital Region
southward. SPC with the latest Day 3 has most of the region in
general thunder with a Marginal Risk (Level 1 of 5) just grazing
Ulster County for an isolated severe threat.

Strong theta-e advection occurs with the wave with PWATs
remaining 1 to 2 STDEVs above normal. Any training of cells or
back building could yield some isolated to scattered instances
of flash flooding. WPC has locations mainly south/southwest of
Albany in a Slight Risk (Level 2 of 4) for potential scattered
instances of flash flooding and a Marginal Risk (Level 1 of 4)
to the north and east. We will have to see where the heavier
rainfall totals occur prior to Wed, as soils may start to get
saturated. At the very least urban and poor drainage
flooding/minor flooding could occur in some locations. A Flood
Watch may also be needed for parts of the region in the future.
The 01Z/NBM 24-hr probabilities for the period ending 12Z/Thu
for >1" rainfall are 50-80% across eastern NY and western New
England. The probs for 2" or greater are mainly less than 25%
for most of the region, except the Mohawk Valley/southwest Dacks
where they are as high as 45-60%. This heavy rain threat bears
watching. It will remain muggy and humid with near normal temps.

The cold front moves through Thu with additional chances of
showers and thunderstorms with some locally heavy rainfall
again. The mid and upper level trough moves across the region
for a isolated to scattered showers continuing into Friday
before cooler, less humid and drier weather is expected for the
holiday weekend.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR conditions continue at KALB, KPSF, and KPOU through 01/00z.
Patchy fog has developed at KGFL this early morning and should
diminish by 13z with VFR conditions returning. For after
01/00z, chances for rain showers arrive at all TAF sites through
the end of the TAF period so continued the mention of light
rain shower activity in either PROB30s or the prevailing
depending on forecast confidence at this time before 01/06z.
Confidence is higher for KALB after 01/01z, with lower
confidence at KGFL, KPSF, and KPOU after 01/00z. Then confidence
increases for TAF sites to begin seeing rain shower activity
after 01/06z with MVFR/IFR conditions.

Winds continue to be light and variable expect for KPSF where west
to northwest winds between 5 and 10 knots continue through 09z when
winds should become calm. Light and variable winds continue
throughout the TAF period.

Outlook...

Tuesday Night: High Operational Impact. Likely SHRA.
Wednesday: High Operational Impact. Definite SHRA...RA...TSRA.
Wednesday Night: High Operational Impact. Definite SHRA...TSRA.
Thursday: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: Moderate Operational Impact. Chance of SHRA.

&&

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

&&

$$

DISCUSSION...15
AVIATION...05