558
FXUS64 KHUN 301806
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
106 PM CDT Wed Sep 30 2026

...New NEAR TERM...

.KEY MESSAGES...
Updated at 105 PM CDT Tue Sep 29 2026

  - Medium to high (40-80%) chances of showers and thunderstorms late
    this week into the weekend, with locally heavy rainfall the
    main concern.

  - Moderate Heat Risk (Level 2/4) in some areas Friday.

&&

.NEAR TERM...
(Tonight)
Issued at 105 PM CDT Wed Sep 30 2026

No significant changes are needed at this time. A clear sky is
expected for the balance of the afternoon heading into the evening
hours. After a warm afternoon in the upper 80s to lower 90s,
temperatures will fall quickly into the 70s after sunset.

Issued at 1113 AM CDT Wed Sep 30 2026

Model guidance continues to hold the upper ridging strongly in
place over the southeast today. 7.34 micron channel satellite
imagery and 12Z Birmingham, AL 7 AM sounding data show very dry
air in place around 850 mb to 700 mb. This area of drier air aloft
will likely be reached as temperatures warm into the lower 80s
today.

We are starting to see this in some area observations near and
west of the I-65 corridor. This mixing of drier air will likely
intensify into the afternoon hours, as temperatures continue to
rise with abundant sunshine into the upper 80s to lower 90s.
Expect RH values to drop into the 15 to 25% range in many areas
later this afternoon.

925 mb winds from the SSE will likely begin to truly get rid of
this drier air aloft over northern Alabama tonight as they increase
to around 20 knots. This change and surface winds around 5 mph
lasting a bit more into the evening hours should help to keep
overnight lows warmer. Lows tonight should only drop into the
upper 50s to lower 60s as a result. Not expecting even much patchy
fog towards daybreak on Thursday.

&&

&&

.SHORT TERM...
(Thursday through Saturday)
Issued at 1113 AM CDT Wed Sep 30 2026

Not much change overall on Thursday, though the center of the
upper ridge shifts east over the Carolinas. NAM12, wants to
produce some isolated showers over NW Alabama. However, given the
strength of the upper ridging at that point and other dry model
output, keeping with no PoP at this time. Likely not much warmer,
given the center of the upper ridge is not directly over northern
Alabama. Highs should again be in the upper 80s to lower 90s. It
will continue to get more humid though, with afternoon dewpoints
in the mid to upper 60s possibly. This will drive heat index
values to around 100 degrees in the hottest locations.

The upper ridging continues to hold in place over the Carolinas
Thursday night, as a decaying longwave axis begins pushing
towards the Tennessee Valley from the Midwest region. Expect the
trend of no rainfall to continue, but low level moisture will
continue to advection into the region ahead of the approaching
upper level trough axis. This should keep lows from dropping below
the upper 60s to lower 70s.

By Friday morning the longwave trough axis continues to weaken in
most guidance. The exception to this is the NAM12 guidance. ECMWF
is the driest and holds off QPF the most into the day on Friday.
Either way by the afternoon hours scattered showers and
thunderstorms do look possible. Shear remains very weak 20 knots
or less mostly, so strong storms do not look likely. However, with
left over tropical moisture pooled ahead of the weak longwave
trough axis, PWATS are forecast to climb to around or slightly
above 2 inches.

However, most guidance continues to weaken the longwave trough
axis Friday night, as the longwave trough axis moves southeast
into the region. Forcing will be a bit of an issue, but the
stalled weak front could produce some scattered areas of heavier
rainfall.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 1113 AM CDT Wed Sep 30 2026

To our west, an upper level trough will begin its swing through
the TN Valley over the weekend. At the surface, an accompanying
cold front will be pushing east. Weak WAA and strong low level
moisture advection will be present along and ahead of this
system. As such, as we move into Saturday morning we will have an
incredibly moist environment present, priming us for a weekend of
heavy rainfall and possible flash flooding concerns.

Through the weekend we will see dew points in the 70s and PWATs
above the 90th percentile per BMX sounding climatology (2"+). This
environment will be favorable for efficient rainfall production.
With persistent forcing from Friday night through Sunday
afternoon, high rain chances (60-80%) are in the forecast all
weekend. Models indicate 2-4 inches of rain from Friday through
Monday. Flooding concerns will arise if periods of heavy rainfall
cause significant amounts of rain to fall in a short period of
time. As such, WPC has issued a Slight Risk (level 2/4) for
excessive rainfall for portions of the area on Saturday into
Sunday. Some uncertainty remains regarding the QPF totals due to
the fact the front and parent trough will be weakening as they
move through. Should the system come through weaker than currently
forecast, QPF amounts could trend down.

The front is currently forecast to pass during the day on Sunday,
however low rain chances and cloud cover look to linger behind the
front through Tuesday. The lingering cloud cover paired with the slow
infiltration of cooler and drier air from the north will keep highs
in the 70s and lows in the 50s for the start of the work week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1122 AM CDT Wed Sep 30 2026

VFR conditions are expected throughout the TAF period.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&

$$

NEAR TERM...17/KTW
SHORT TERM....KTW
LONG TERM....KTW
AVIATION...KTW