403
FXUS64 KHUN 021149
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
649 AM CDT Tue Sep 2 2025

...New AVIATION...

.NEAR TERM...
(Today)
Issued at 405 AM CDT Tue Sep 2 2025

In the mid/upper-levels, our forecast area remains under the
influence of a closed 500-mb cyclone that will gradually intensify
over the course of the near term period as it lifts northward
from the Mid-Atlantic states into southeastern
Ontario/southwestern Quebec. Embedded within prevailing WNW flow
aloft of 20-25 knots around the low, a shortwave trough (initially
across eastern KS/western MO) will track east-southeastward into
the TN Valley by late this afternoon. Although this feature is
predicted to deamplify with time, a minor increase in deep-layer
ascent downstream from it should contribute to rapid development
of showers and thunderstorms along and immediately east of a
surface trough currently lying from northern MS through western TN
and into southwestern KY. Present indications are that convective
initiation will likely begin in the 10-12Z timeframe, with
conditions across the majority of the CWFA through sunrise
characterized by an overcast coverage of mid-level clouds and a
few sprinkles of rain, with temps in the m-u 60s.

Rain and embedded thunderstorms will expand in coverage across
the western/central portions of the forecast area during the late
morning hours, but this regime will likely have difficulty
expanding into our southeastern counties this afternoon as it will
encounter a progressively drier and more stable airmass related
to a weakening cold air damming event in the lee of the southern
Appalachians. With weak vertical wind shear in place and CAPE
perhaps being limited by early development of convection (around
or shortly after sunrise), the primary impacts from this event
will be locally heavy rainfall and occasional lightning (although
a few strong wind gusts up to 30-40 MPH may occur with the most
dominant updrafts). Due to these factors, highs will be a bit
cooler today, ranging from the m-u 70s in elevated terrain to the
l-m 80s in the valley.

As skies clear in the wake of morning precipitation,
redevelopment of thunderstorms may occur later this afternoon in
the vicinity of the surface trough to our northwest, and this
activity may eventually begin to congeal and spread southeastward.
However, this would likely not be a concern for our forecast area
until this evening.

&&

.SHORT TERM...
(Tuesday night through Thursday Night)
Issued at 1044 PM CDT Mon Sep 1 2025

Once again, any afternoon convection on Tuesday will wane with
the setting sun and loss of diurnal heating. With the upper level
trough remaining entrenched across much of the eastern CONUS, not
much change in the weather pattern. On Wed and Thu a few
shortwaves will swing through the area bringing chances for
showers and thunderstorms with the greatest chances during the
peak heating hours. A few strong storms may occur given marginal
shear and instability, but heavy rainfall will be the main threat.
Especially in areas that see multiple rounds across a few days.
Outside of storms, mild conditions both Wed and Thu are forecast
with highs in the mid to upper 80s and overnight lows in the low
to mid 60s.

&&

.LONG TERM...
(Friday through Monday)
Issued at 1044 PM CDT Mon Sep 1 2025

A little bad news for the fans of early fall weather, the long term
pattern looks a little warmer than previously expected as the work
week comes to a close and we head into the weekend. The upper trough
axis will pivot east of the area as an additional wave starts to dig
south over the Great Lakes toward the weekend. A strong cold front
will push south through the OH River Valley and approach the TN River
Valley late Friday into Saturday but is expected to stall near or
just to our north. Where exactly this front stalls will have a
fairly big impact on the temperatures as areas south of the front
will experience temps in the upper 80s to lower 90s where areas north
of the front will drop to the 70s and lower 80s. Friday looks to be
the warmest day with highs in the upper 80s to mid 90s. With the
drier air in place, heat indices are expected to stay pretty close to
air temperatures so we are not expecting any heat related headlines
currently. The front is forecast to move little over the weekend
and will feature temps in the 80s with a low chance for rain and
thunderstorms on Saturday. Overnight lows will fall into the 50s and
lower 60s Saturday and Sunday nights before a pattern shift begins to
bring in warmer conditions on Monday. Stay tuned for forecast updates
throughout the week!

&&

.AVIATION...
(12Z TAFS)
Issued at 649 AM CDT Tue Sep 2 2025

There have been no major changes to previous aviation forecast
reasoning, as current radar data depicts an expanding region of
rain and embedded TSRA btwn MSL-HSV, which will largely impact
MSL/12-16Z and HSV/14-18Z. Although storms are not expected to be
strong, AWWs for occasional lightning may be warranted at times. A
second round of convection may evolve to our northwest later this
aftn (which could potentially spread southeastward into northern
AL this evening), and PROB30 groups have been included for this
activity from 22-2Z. Outside of convection, we expect VFR conds to
prevail with cloud bases near 3500 ft for much of the day. Sfc
winds will remain from the SE at speeds arnd 5 kts today, before
becoming lgt/vrbl this evening.

&&

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

&&

$$

NEAR TERM...70/DD
SHORT TERM...GH
LONG TERM...25
AVIATION...70/DD