583
FXUS64 KHUN 161634
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1134 AM CDT Sun Aug 16 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1045 AM CDT Sun Aug 16 2026

 - Dangerous heat will impact the Tennessee Valley through the
   middle of this week, with Major (Level 3/4) to Extreme (Level
   4/4) heat impacts forecast.

 - A Heat Advisory is in effect for all of northern Alabama and
   southern middle Tennessee through 7 PM Monday, with extensions
   on the table in future updates through potentially mid-week.

 - A Slight (2 out of 5) risk for severe thunderstorms is forecast
   Monday across eastern Franklin County Tennessee and portions
   of far northeast Alabama, with a Marginal (1 out of 5) risk
   through most of the area.

&&

.NEAR TERM...
(Rest of Today and Tonight)
Issued at 1045 AM CDT Sun Aug 16 2026

The primary concern continues to be heat as an upper level ridge
procrastinates moving eastward and we remain in a favorable area
for above normal temperatures. This afternoon`s highs are forecast
to warm into the mid to upper 90s with heat indices up to 102-109
degrees. Tonight, lows are forecast to drop into the mid to upper
70s, which will not provide much relief. A Heat Advisory continues
through 7 PM Monday. Be sure to stay hydrated and seek shade when
outdoors to avoid heat-related illness.

&&

.SHORT TERM...
(Monday through Wednesday)
Issued at 1045 AM CDT Sun Aug 16 2026

An area of low pressure pushing eastward through the Great Lakes
region is forecast to bring an associated cold front southeastward
into the Tennessee Valley and Appalachian region Monday night.
Ahead of this, both heat and severe storms will be on the table as
hazards Monday afternoon into the evening hours. Addressing the
heat, highs are forecast to reach the mid to upper 90s yet again
along with heat indices nearing 110. The recent HREF run has very
low chances (less than 5%) of our area meeting or exceeding 110
degree heat indices Monday afternoon, with the most likely range
being around 105-108 degrees. Thunderstorm development and
coexisting cloud cover ahead of the cold front will be the factor
to watch. If the front slows down and the thunderstorms are
delayed, there is a low chance we could reach Extreme Heat Warning
in some locations (especially urban heat island spots such as
Huntsville). We have opted to hold off on upgrading for now, but
do not rule it out in future updates as the forecast evolves.

Severe weather-wise, the Storm Prediction Center has included most
of the area in a Marginal risk (level 1 of 5) and clipped portions
of northeastern AL and southern middle TN in a Slight risk (level
2 of 5). The primary concern with any storms that are realized
will be damaging winds up to 60 mph in addition to heavy rainfall
and lightning. Model soundings continue to portray steep low level
lapse rates (9+ C/km) combined with DCAPE values over 1100 J/kg as
well as MLCAPE over 1400 J/kg. These factors, combined with the
typical inverted V sounding profile, will attribute to an
increased risk of downbursts through the afternoon into the
early evening hours. PWAT values are in the range of 1.7-1.9",
which is near 90th percentile per BMX sounding climatology.
Combined with the forecast slow storm movement (less than 10 kts),
heavy rainfall will bring a low chance of flash flooding which
will primarily be in areas of poor drainage. Heavy downpours will
cause temporary ponding of water on roadways, which will create
hazardous driving conditions during and shortly after any
rainfall. Shear continues to look less than impressive with a lack
of low level vorticity and therefore not anticipating tornadoes
to be a threat. Be sure to stay weather aware Monday and have
multiple ways to receive warning information throughout the
afternoon.

Tuesday through Wednesday, heat remains a hazard with highs
forecast to reach the 90s both days along with heat indices up to
105 degrees. A low chance of an extension of the current Heat
Advisory (valid through 7 PM Monday) exists if temperatures
continue to trend higher. Otherwise, dry conditions are forecast
through both days after the cold front shifts south of the area.

&&

.LONG TERM...
(Tuesday night through Saturday)
Issued at 1042 PM CDT Sat Aug 15 2026

The weather looks dry on Wednesday, as NW flow continues and
otherwise conditions look similar to temperatures and heat index
values expected the previous day.

Even cooler temperatures are expected towards the end of next
week, as another stronger front moves southeast into the area and
stalls. Shower and thunderstorm chances may increase more as we
get closer to this period. Highs in the upper 80s to lower 90s are
expected with the increasing cloud cover and precipitation
chances.

&&

.AVIATION...
(18Z TAFS)
Issued at 1134 AM CDT Sun Aug 16 2026

VFR conditions are forecast through the TAF period.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory until 7 PM CDT Monday for ALZ001>010-016.

TN...Heat Advisory until 7 PM CDT Monday for TNZ076-096-097.

&&

$$

NEAR TERM...HC
SHORT TERM....HC
LONG TERM....KTW
AVIATION...HC