234
FXUS64 KHUN 112000
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
300 PM CDT Tue Aug 11 2026

...New NEAR TERM...

.KEY MESSAGES...
Updated at 959 AM CDT Tue Aug 11 2026

 - A Heat Advisory is in effect for the whole area Wednesday
   through Friday with extensions and upgrades likely through the
   weekend.

 - A low conditional threat for strong to severe storms exists
   this afternoon and Wednesday afternoon. Please check back for
   updates.

&&

.NEAR TERM...
(Tonight)
Issued at 300 PM CDT Tue Aug 11 2026

Scattered afternoon showers and thunderstorms have developed
mainly over NE AL. Low to medium chances of showers and storms
will remain through the afternoon with heavy rain being the
primary threat. Heat will be of more widespread interest through
the remainder of the day. Temperatures and dew points have over
preformed in some locations allowing for wide spread 100F+ heat
indices with some locations seeing near and above 105F+. Even so,
dew points have begun to mix out some. This paired with scattered
shower coverage will dissuade widespread 105F+ heat indices and
thus we will maintain our Heat Advisory starting tomorrow.
Nevertheless, please make sure to practice proper heat safety if
spending time outdoors.

Diurnal convection will die off shortly after sunset however
uncertainty remains regarding additional storm chances. SPC has
highlighted a risk for additional storms to drop into the area
late this evening in association with a dying MCS. Models show
the MCS decaying to our north but differ significantly regarding
how far south and west storms may linger. If storms do make it
across the CWA border it looks like they would come between
midnight to 2 AM and pose little to no severe risk. Any
showers/storms that do make it would be gone by sunrise.

&&

.SHORT TERM...
(Wednesday through Friday)
Issued at 959 AM CDT Tue Aug 11 2026

Through the short term heat will be our main concern. Ridging will
continue to build with the TN Valley being directly under the
ridge by the end of the week. This will promote a warming trend in
temperatures with highs warming from the low to mid 90s on
Wednesday to the high 90s by Friday. With light SSW flow, dew
points will remain in the 70s making for very muggy conditions. Being
directly under the ridge will also further suppress rain chances
meaning there will be little relief from the high temps and dew
points. Thus, we have high confidence in seeing heat indices above
100 area wide with most locations seeing 105F+ during peak
heating. As such, a Heat Advisory has been issued for the whole
area from Wednesday through Friday with extensions and possible
upgrades to an Extreme Heat Warning likely through the weekend.
Heat compounds its effects on the body so please make sure to take
proper precautions if spending time outdoors.

It is necessary to again acknowledge the marginal risk SPC has
issued for portions of the area on Wednesday too. This risk for
strong to severe storms largely follows the same reasoning as
todays risk with it being tied to what happens upstream. We
currently maintain a low risk of outflow driven storms entering
our area tomorrow afternoon and will more than likely remain
mostly dry area wide. Please check back for updates as this is
subject to change.

&&

.LONG TERM...
(Thursday night through Monday)
Issued at 1010 PM CDT Mon Aug 10 2026

Models really strengthen the upper ridge over the Deep South
Thursday night into Friday. Model guidance hints at a very strong
597 or 598 decameter high pressure center with this feature. This
upper ridge will produce very strong subsidence over the area and
should keep any moderate to high shower/storm chances well to our
north and east of the area. 925 mb temperatures climb to between
28 and 30 degrees in most guidance by Friday afternoon. This will
likely push high temperatures into the 95 to 99 degree range at
least with good insolation through the day. A high or two of 100
degrees is not out of the question. It does look like some mixing
of drier air below 800 mb will occur with the strong subsidence.
This will likely lower afternoon dewpoints, maybe more than
currently lowered in straight NBM guidance. For now, lowered
dewpoints only conservatively for now from NBM (75% NBM/25%
CONSRAW). Still, heat index values above 105 degrees look like a
good bet (though some uncertainty exists if 108 or above heat
index values will be met in many locations). However, if NBM
guidance is correct and less mixing occurs, these values may be
more widespread and extreme heat products may be needed for some
areas.

Either way a heat wave will continue into the weekend, as the
upper ridge either remain as strong or strengthens a bit more. Some
guidance on Saturday and Sunday push 925 mb temperatures into the 29
to 32 degree range (likely values closer to 32 degrees in NW AL).
This could push afternoon highs with strong low level subsidence
continuing over the century mark at more locations. With the
highs possibly being a few degrees higher over the weekend, even
if mixing occurs, extreme heat looks most likely to occur then.

A few models (GFS in particular) try to extend a front into the
southeast Sunday afternoon. However, given the strength of the upper
ridge, this looks very dubious. If that does happen, then highs will
likely be a bit less hot and remain in the mid/upper 90s versus
upper 90s to over 100 degrees. The bigger impact would be a focusing
of lower level moisture/higher dewpoints over the area Sunday
afternoon, which would drive heat index values higher despite lower
high temperatures. Whichever solution is correct, heat index values
look to still climb to between 105 and 108 degrees at least on Sunday
afternoon.

By early next week, models do seem to convergence on a solution that
slides the center of the upper ridge WNW over Texas and puts the
Tennessee Valley region in a more NW flow aloft. This should bring
some increase in afternoon shower/storm activity and likely more
afternoon cloud cover to the area. 925 mb temperatures will still
climb into the 23 to 27 degree though, so highs in the mid 90s at
least will likely still continue. However, this drop in highs, may
make the oppressive heat less widespread.

&&

.AVIATION...
(18Z TAFS)
Issued at 1150 AM CDT Tue Aug 11 2026

VFR conditions are largely forecast to prevail through the whole
TAF period. There is a low chance of afternoon thunderstorms with
best chances in NE AL, thus VCTS has been included at HSV. While
chances are lower at MSL, if a storm moved directly over either
terminals amendments will be needed. Tonight there will again be
a low chance of fog during the early morning hours. Confidence in
location and intensity is too low to include in the TAF at this
time.

&&

.CLIMATE...
Issued at 301 AM CDT Tue Aug 11 2026

The Climate Prediction Center has included the whole area in a
Moderate to a High Risk for Much Above Normal Temperatures for
August 18th through August 22nd. The High Risk includes locations
south of a line from Lexington, to Athens, New Hope and Fort
Payne. The Moderate Risk include locations north of that line.
Therefore, there is a 40-60% chance in the Moderate Risk locations
and a 60-80% chance for those in the High Risk areas for
temperatures above 95-97 degrees F during this period.

More information on the CPC U.S. Hazards Outlook can be found at:
https://www.cpc.ncep.noaa.gov/products/predictions/threats/threats.php

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory from 1 PM Wednesday to 7 PM CDT Friday for
     ALZ001>010-016.

TN...Heat Advisory from 1 PM Wednesday to 7 PM CDT Friday for TNZ076-
     096-097.

&&

$$

NEAR TERM...RAD
SHORT TERM....RAD
LONG TERM....KTW
AVIATION...RAD