Area Forecast Discussion
Issued by NWS Huntsville, AL

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757
FXUS64 KHUN 211116
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
616 AM CDT Fri Aug 21 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 409 AM CDT Fri Aug 21 2026

 - Areal flooding will continue to impact the eastern half of
   north AL through the early morning hours.

 - A slightly cooler/drier airmass will spread across the region
   later today. However, this will be short-lived with additional
   showers and thunderstorms possible beginning Saturday evening
   and continuing through much of next week.

&&

.NEAR TERM...
(Today)
Issued at 409 AM CDT Fri Aug 21 2026

Severe thunderstorms (which impacted much of the region with
damaging winds, hail, excessive lightning and flooding rainfall
yesterday evening) have largely dissipated to the south/east of
the forecast area. However, another loosely organized complex of
convection (which initiated along the same frontal confluence
axis) is currently spreading southeastward across northern MS.
Most high-resolution model data suggests that this activity will
bypass our region to the southwest before decaying across west-
central AL by 12Z, but due to lingering runoff and residual
flooding from the widespread 2-4" rainfall event, Areal Flood
Warnings will remain in effect for the eastern half of north AL
through 5 AM CDT. Although environmental conditions currently
support development of patchy, locally dense fog as early morning
temps remain steady in the l70s, there have thus far been no
indications of widespread fog formation.

Over the course of the day, light northerly flow at the surface
(coupled with strengthening NW flow aloft) will advect a slightly
drier airmass into the local forecast area, with dewpoints by late
afternoon expected to range from the m60s in the north to the
u60s-l70s in the south. A few afternoon showers (and perhaps a
thunderstorm or two) may develop in the vicinity of the Cumberland
Plateau, but it appears as if more robust convection (related to
the southward sagging cold front and boundary layer moisture
gradient) will be focused across central AL and points southward.
Thus, we will retain only a low 15-25% POP for much of the
forecast area. With the combination of falling dewpoints and a
broken layer of postfrontal stratocu expected to result in much
lower CAPE (compared to yesterday), any thunderstorm activity that
may materialize in our region will remain well below severe
thresholds. Afternoon high temps will be several degrees cooler,
ranging from the m80s in elevated terrain to the u80s-l90s
elsewhere.

&&

.SHORT TERM...
(Saturday through Sunday Night)
Issued at 741 PM CDT Thu Aug 20 2026

Any remaining MCS clusters will shift south of the TN valley by
Friday morning. There is a very low chance of a shower or
thunderstorm along the cold front that will slip southeast into
the TN valley on Friday, but the chance is less than 15%. Dry
weather should last through Saturday. But then another northwest
flow shortwave and cold front arrives Saturday night which may
generate showers and thunderstorms in the eastern OH valley into
eastern TN. It is unclear if thunderstorms will be able to
develop southwest into the TN Valley Saturday evening or
overnight. We will monitor model trends, but for now most areas
will remain dry in the forecast. Dew points should drop into the
60s by Sunday behind this front which will be a welcome relief
from the higher dew points we have experienced lately.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 741 PM CDT Thu Aug 20 2026

A mean trough axis will remain in place over the eastern CONUS with a
strong ridge over the southern Rockies into the southern Plains. This
will keep a fairly active northwest flow regime over the central
Plains and upper Midwest through the OH and TN valleys. This will
keep at least low chances of showers and thunderstorms in play, with
the big question begin details of MCS timing and intensity. It`s far
too early to discern this with much confidence, so will side with the
NBM in this forecast. High temperatures will remain near normal in
the upper 80s to lower 90s with lows in the 60s to around 70.

&&

.AVIATION...
(12Z TAFS)
Issued at 616 AM CDT Fri Aug 21 2026

Although the remnants of evening TSRA continue to dissipate well
to our southeast early this morning, another small but weakening
complex of storms will track southeastward (safely to the S/W of
both HSV and MSL) early in the TAF period. With only a few
afternoon convective cells possible along the Cumberland Plateau
(and frontal convection expected to initiate across central AL),
we will keep the forecast dry at this point. Thus, VFR conds will
exist, with development of a sct-bkn stratocu field by 15Z
(followed by rapid clearing around 0Z). Sfc winds will remain from
360-020 at sustained speeds of 5-10 kts.

&&

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

&&

$$

NEAR TERM...70/DD
SHORT TERM...17
LONG TERM...17
AVIATION...70/DD