textproduct: NWS Birmingham

KEY MESSAGES

Issued at 103 PM CDT SAT JUL 18 2026

- Thunderstorms: Medium to high rain and thunderstorm chances expected over the weekend.

- Heat: Minor to moderate heat risk through the weekend, transitioning to a major heat risk early next week with heat indices potentially reaching 105 degrees.

DISCUSSION

(This afternoon through Friday) Issued at 103 PM CDT SAT JUL 18 2026

Surface high pressure to the west will keep northerly flow over the state. Activity developing this afternoon will keep the same north to south movement as the past few days. Instability this afternoon is greater than 3,000 J/kg with steep lapse rates and LI around -8 and -9. The wind profile is fairly weak, and oriented north to south. PW values around max climatologically for this time of year and slow moving storms could lead to heavy rain rates and totals, especially in areas with training storms. Flooding may be a concern in these areas, and will have to keep an eye on urban, slow drainage, and low lying areas. Otherwise, strong to possibly severe thunderstorms are possible as these storms build and collapse, producing outflow and sub severe hail. CAMs handle afternoon thunderstorm coverage terribly, so increased rain chances through the afternoon and evening to reflect greater coverage than models forecast.

By tonight and Sunday, a low pressure in the Gulf is expected to meander west and linger south of the state. Models differ on the location of this low, with several high res models showing a strengthening off the coast. This low and the high pressure to our west, will keep chaotic winds over the state, with a light wind profile. Instability, PW, and other parameters will remain nearly the same, with scattered to widespread thunderstorms again expected Sunday afternoon and evening. Monday the low is expected to remain in the Gulf, with low level winds over the state transitioning to out of the south and south east around this low. This could bring increased moisture and warmer air, as well as increased winds to the southeastern counties with stronger mid level winds moving into the state. Afternoon and evening convection is again expected Monday, with slightly more shear in the southeast. Overall severe weather still not expected, though storms could be strong to isolated severe with damaging winds the main threats.

By Monday night and Tuesday, models start to diverge on what happens to that low in the Gulf. A low pressure system moves across the Great Lakes during this time and swings a boundary through the TN Valley. At the same time a high pressure will slowly build in from the west. A few models have this low in the Gulf weakening and moving to the northeast into the state and towards that boundary, while others have the low moving west into the western Gulf and moving with the flow around that high pressure. Either way, afternoon showers and thunderstorms should be possible each afternoon through mid week. The boundary associated with that low will move through the state by Thursday. Northerly flow setting up behind the boundary will bring slightly cooler and drier air, which will help the heat that builds in for the first half of the week. Lowest heat indices could be around 105 degrees for several days during the beginning of the work week.

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AVIATION

(18Z TAFS) Issued at 103 PM CDT SAT JUL 18 2026

Scattered afternoon thunderstorms and thunderstorms will move through the state through the evening, weakening after sunset. Included a VCSH or VCTS for every site, with PROB30 to account for the isolated stronger activity. Overnight, VFR conditions will prevail, with isolated to scattered activity again by late morning and early afternoon Sunday. Left mention of this activity out of each TAF for now, due to the low confidence and timing late in the TAF period.

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

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FIRE WEATHER

The warm and humid air mass will continue through the next several days across Central AL. Increasing tropical moisture associated with a weak disturbance in the Eastern Gulf is expected across the area over the weekend, which will increase rain chances each afternoon. There are no critical fire weather concerns at this time.

PRELIMINARY POINT TEMPS/POPS

Gadsden 73 92 72 92 / 10 50 40 50 Anniston 73 92 73 92 / 10 50 40 40 Birmingham 75 94 75 93 / 10 50 40 40 Tuscaloosa 75 95 75 94 / 0 40 40 30 Calera 74 96 74 96 / 10 50 40 40 Auburn 74 91 74 91 / 30 50 40 30 Montgomery 74 94 74 94 / 20 50 40 30 Troy 72 91 72 92 / 40 60 30 40

BMX WATCHES/WARNINGS/ADVISORIES

None.