textproduct: NWS Birmingham

KEY MESSAGES

Issued at 605 AM CDT WED AUG 19 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.

- Severe Storms: A marginal (Level 1 of 5) risk for severe thunderstorms is forecast for areas generally near and west of Interstate 65 today from 2 pm through 10 pm. Damaging winds are the primary risk.

DISCUSSION

(Today through Tuesday) Issued at 147 AM CDT WED AUG 19 2026

Some high-resolution guidance depicts some of the activity associated with the expected mesoscale convective system that affects the Mid-South region to our northwest today to migrate further to the southeast and affect the western portions of the area this afternoon through the evening hours. Hot temperatures along with persistent high humidity will result in strong surface- based instability while some drier air aloft will create favorable wet microburst conditions that will favor damaging winds being the primary risk with the heavier activity. Grids have been updated to reflect this potential with risk graphics in process of being created and disseminated.

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Previous Discussion:

By tomorrow, the apex of the upper-level ridge will have moved west, planting itself near the Four Corners. However, this ridge will remain slightly suppressed for the next 48-hours, keeping the trough over the Midwest north of the state. Because of that, afternoon Heat Index values will continue to meet Heat Advisory criteria for portions of our area, with one remaining in effect through tomorrow afternoon. Confidence is high that we'll need another Heat Advisory for some locations on Thursday, but this should be the last one needed before the upper-level pattern really begins to shift.

By early Friday morning, a longwave trough will begin to take shape over Quebec and Ontario, deepening the trough situated over the Midwest. This trough should start to infiltrate the Tennessee River Valley by Friday afternoon, bringing along with it increased shower and thunderstorm chances. Given the location of this trough, organized rain chances should stay in the forecast through the weekend, before it shifts to the east come Monday. This shift will allow for drier air to filter back into the area, allowing for peak heat index values to remain below advisory thresholds into the start of the new workweek.

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AVIATION

(12Z TAFS) Issued at 605 AM CDT WED AUG 19 2026

Other than a brief period of reduced visibility at MGM early this morning, VFR conditions prevail areawide. Expect scattered cumulus development as early as midday and continuing through the afternoon. Heavier shower and storm activity to our northwest may extend further south into our western counties during the afternoon and into the evening hours. A PROB30 tempo was added to TCL from 21z to 00z to account for this risk.

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

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 97 73 97 73 / 0 0 30 30 Anniston 94 72 95 72 / 0 0 30 30 Birmingham 95 75 96 75 / 20 0 30 40 Tuscaloosa 99 76 99 75 / 30 20 30 30 Calera 96 74 97 74 / 20 10 30 30 Auburn 93 74 94 75 / 0 0 30 30 Montgomery 97 75 99 74 / 20 10 20 30 Troy 96 73 98 73 / 10 10 20 20

BMX WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 9 PM CDT this evening 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.