641
FXUS64 KHUN 170550
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1250 AM CDT Fri Jul 17 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 918 PM CDT Thu Jul 16 2026

 - Expect low to medium chances of showers and thunderstorms on
   Friday, with medium to high chances of showers and storms
   Saturday and Sunday.

 - Near seasonable temperatures are forecast for the upcoming
   weekend.

 - Moderate HeatRisk (Level 2 of 4) are forecast Friday and this
   weekend, with Heat Index values peaking in the upper 90s to 105
   degrees. Major (Level 3 of 4) HeatRisk are forecast next
   Tuesday.

&&

.NEAR TERM...
(Rest of tonight and Friday)
Issued at 918 PM CDT Thu Jul 16 2026

In a larger view, upper level troughing was present across the
Pacific NW, with broad upper ridging across most of the CONUS. A
zonal west-east polar flow was moving over the United States and
Canada border. This flow as it was oriented in a slight ESE manner
across the Mid Atlantic, was helping to keep smoke from Canadian
fires well north of this area.

Locally, available moisture and resultant instability from earlier
daytime heating has resulted in isolated showers across portions
of the Tennessee Valley. Shower and thunderstorm activity was a
bit more plentiful to our north and east, with slightly higher
amounts of precipitable water and more boundary interaction. With
an exception of isolated showers SW of Muscle Shoals, other
activity for the most part has dissipated. 9 PM temperatures were
falling through the upper 70s/lower 80s, after earlier highs were
around 90. As we go into the latter half of July with slightly
longer nights, we cannot rule out predawn patchy fog development
mainly in and near those more favored areas.

With high pressure at the surface and aloft over the area, expect
similar conditions to close out the work week Friday. Expect
another very warm to hot day, with highs rising into the upper 80s
to lower 90s, with heat index values from the upper 90s to 103.
The strong daytime heating of a slightly more humid airmass will
result in scattered to numerous showers and thunderstorms forming
in the afternoon to early evening. Convection should remain
"general" in intensity, with the usual strong gusty outflow winds,
frequent lightning, and heavy downpours.

&&

.SHORT TERM...
(Friday night through Sunday)
Issued at 918 PM CDT Thu Jul 16 2026

Shower activity should diminish in coverage and intensity Fri
evening with the loss of daytime heating. Low temperatures by
daybreak Sat should cool only into the lower 70s. Another repeat
performance later for both days Sat and Sun, as daytime heating
and resultant higher instability bring more afternoon to early
evening shower and thunderstorm development. Similar storm
intensity with gusty winds, frequent lightning, and heavy
downpours. High temperatures both days should rise to around 90,
with heat indexes from the upper 90s to 105 (very spotty coverage
of the hottest values). Depending upon trends, Heat Advisory
criteria could be met over the weekend should high temperatures
rise a bit more and/or cover a larger area. This will be evaluated
in future forecasts.

&&

.LONG TERM...
(Sunday night through Thursday)
Issued at 918 PM CDT Thu Jul 16 2026

On Monday, a deep layer narrow trough axis will be located across
the eastern Gulf of America as a strong upper trough begins to
dig southeast through the eastern Great Lakes and a strong
anticyclone builds across the south central U.S. The ridge builds
east into the Southeast U.S. Tuesday before the strong upper
trough swings a cool front southeast through the Mid Atlantic into
the TN Valley on Wednesday. Shower and thunderstorm chances will
remain 20% or less during this period with the ridge in place, and
despite a frontal passage. Temperatures will warm into the 90-95F
range Monday and Tuesday, then drop into the upper 80s to lower
90s on Wednesday, and middle 80s to around 90 on Thursday. The
Heat Risk level will reach Major (3 out of 4) on Tuesday when heat
index values reach 100-105F for most areas and WBGTs reach the
middle to upper 80s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1250 AM CDT Fri Jul 17 2026

VFR conditions are forecast to persist through much of the
overnight hours however there is a low chance fog could develop if
cloud cover stays minimal. Winds should remain near calm into the
morning hours with increasing chances for showers and
thunderstorms toward the afternoon, especially near KHSV.
Reductions to MVFR or lower categories will be likely during
thunderstorms, otherwise VFR conditions are forecast to persist.

&&

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

$$

NEAR TERM...RSB
SHORT TERM....RSB
LONG TERM....17
AVIATION...25