textproduct: NWS Birmingham

KEY MESSAGES

Issued at 1244 PM CDT MON AUG 17 2026

- Heat: Drier air filters in for some relief across the northern half of the area on Tuesday. Major heat risk will continue for the southern and southwest portion of the area with Heat indices of 104 to 109 degrees. A heat advisory will be needed for portions of the area Tuesday.

- Thunderstorms possible tonight across the northern half the area. Some storms could be severe with damaging winds. Storms possible again Tuesday across mainly the area within the heat advisory. Primary hazards will be lightning and damaging winds.

DISCUSSION

(This afternoon through Sunday) Issued at 1244 PM CDT MON AUG 17 2026

The region currently sits on the eastern edge of a rather flat mid level ridge centered over the southern plains and the southwest US. A weak disturbance in the flow aloft migrates through the TN valley tonight which triggers TS activity along an accompanying boundary separating the oppressive heat and humidity from a slightly drier airmass to the north. The good news is there is enough of a push of the mid 60 dewpoints to allow the heat products to expire for areas along and northeast of a Chambers to Shelby to Lamar county line. South and west of that line, a heat advisory will again be in effect for Tuesday as dewpoints still sit in the mid 70s and max heat indices will range from 104 to 109 on Tuesday.

Likely to see something similar in place for Wednesday and Thursday as the drier air, albeit helpful to keep HI down for the northeastern portion of the CWA, slowly erodes and dewpoints creep back into the 70s areawide by Friday. In the upper levels, the mid level ridge begins to strengthen over the western US this weekend allowing for energy to carve south into the eastern periphery and put the region in the base of a trof between the break between the western ridge and the Bermuda ridge. Some guidance pointing to a stormy Friday as that feature evolves and sinks south, but, will need to see some more consistency in the guidance as we get closer. Regardless as a result of the trof position, drier air filters in area wide by Sunday.

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AVIATION

Typical summertime pattern in store this TAF cycle with VFR conditions expected outside of any convective activity. CU field develops today with TS development after 20z. Kept prob30 in through the evening to account for sagging line of TS which may encroach on northern sites this evening. Winds will be generally light and out of the west except in TS where boundaries could account for gusts to 20 or 30kts and any direction.

PRELIMINARY POINT TEMPS/POPS

Gadsden 75 94 68 97 / 40 0 0 0 Anniston 74 93 68 95 / 30 0 0 0 Birmingham 76 93 72 96 / 30 0 0 0 Tuscaloosa 77 97 73 100 / 20 10 10 0 Calera 75 95 71 97 / 30 0 10 0 Auburn 76 92 72 93 / 20 0 10 0 Montgomery 77 99 73 99 / 10 10 20 0 Troy 75 97 73 97 / 10 20 20 0

BMX WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 9 PM CDT this evening for the following counties: Autauga-Barbour-Bibb-Blount-Bullock-Calhoun- Chambers-Cherokee-Chilton-Clay-Cleburne-Coosa-Dallas-Elmore- Etowah-Fayette-Greene-Hale-Jefferson-Lamar-Lee-Lowndes-Macon- Marengo-Marion-Montgomery-Perry-Pickens-Pike-Randolph-Russell- Shelby-St. Clair-Sumter-Talladega-Tallapoosa-Tuscaloosa-Walker- Winston.