Severe Thunderstorm Warning 148, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
621 PM CDT Tue Aug 18 2026

...New AVIATION...

.KEY MESSAGES...
Issued at 620 PM CDT TUE AUG 18 2026

- Heat: Major HeatRisk is expected to persist through the middle
  of the workweek.  Heat indices are forecast between 103 to 109
  degrees. A Heat Advisory is now in effect for portions of
  central Alabama through Wednesday.

- Thunderstorms: Isolated afternoon thunderstorms will remain in
  the forecast through Thursday, especially south of I-20. More
  organized rain chances will increase closer to the weekend, as a
  series of disturbances moves through the region.

&&

.DISCUSSION...
(This afternoon through Monday)
Issued at 202 PM CDT TUE AUG 18 2026

The upper-level ridge currently dominating the forecast will
shift westward over the coming days, allowing a deep trough over
the Midwest to influence the region. While temperatures will see
a slight downward trend, Heat Advisory criteria are expected to
persist in parts of the area through Wednesday before conditions
ease by Friday into the weekend. As the Midwestern trough
deepens, weak shortwaves will track across the region.

Organized rain is anticipated Friday through the weekend, though
confidence regarding coverage and rainfall totals remains low.
The deepening trough will facilitate the arrival of drier air,
driving peak heat index values below advisory thresholds through
the weekend. We increased rain chances above consensus for
tonight and Wednesday, accounting for model performance
limitations. High temperatures are anticipated to remain in the
low to mid-90s into early next week.

16

&&

.AVIATION...
(00Z TAFS)
Issued at 620 PM CDT TUE AUG 18 2026

Thunderstorms will remain in the forecast through 19/02z, with
TCL, EET, and MGM maintaining TEMPO groups through then. Once
thunderstorm activity diminishes, there is high confidence in VFR
conditions for the remainder of the TAF period.

Note: AMD NOT SKED for AUO due to a weather observation outage.

/44/

&&

.FIRE WEATHER...

MinRH values will generally range between 35 and 45% the next few
days, before slowly climbing into the weekend ahead of increasing
rain chances. Winds will remain light the next few days, before
increasing into the weekend as well. Fire weather concerns are
currently low, but they will start to increase by Monday no
meaningful rainfall occurs with this weekend's system.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     69  96  72  97 /   0  10   0  10
Anniston    70  93  71  95 /  10  10   0  10
Birmingham  73  95  74  95 /  10  10   0  10
Tuscaloosa  74  99  75  99 /  20  10   0  20
Calera      73  95  73  96 /  20  10   0  20
Auburn      74  92  73  94 /  10  10   0  20
Montgomery  74  97  74  98 /  40  10  10  20
Troy        73  95  73  97 /  40  20   0  30

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT Wednesday for the following
counties: Autauga-Bibb-Chilton-Coosa-Dallas-Elmore-Fayette-
Greene-Hale-Jefferson-Lamar-Lowndes-Marengo-Marion-Montgomery-
Perry-Pickens-Shelby-Sumter-Tuscaloosa-Walker.

Heat Advisory until 9 PM CDT this evening for the following
counties: Barbour-Bullock-Lee-Macon-Pike-Russell.

&&

DISCUSSION...16
AVIATION.../44/

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