textproduct: Huntsville

KEY MESSAGES

Updated at 937 PM CDT Fri Sep 4 2026

- A Heat Advisory remains in effect through 8 PM Sunday due to Major to Extreme HeatRisk, along with afternoon heat indices rising up to 105-109 degrees in portions of the forecast area.

- A low chance (30% or less) of thunderstorms are forecast Saturday afternoon into the late evening, with a low chance of some becoming severe. Damaging winds will be the primary threat is any strong to severe storms.

NEAR TERM

(Rest of tonight and Saturday) Issued at 937 PM CDT Fri Sep 4 2026

Showers and thunderstorms that formed earlier this evening have since subsided and dry conditions are forecast overnight. Mostly clear skies coupled with light winds will support a patchy fog risk over areas with smaller dew point depressions and areas that saw rain earlier. Recent model runs keep smaller dew point depressions along and west of I-65, so confidence is higher in at least patchy fog forming there overnight into early Saturday. If any fog is realized, it will dissipate shortly after sunrise. Overnight lows are forecast to drop into the mid 70s, providing little relief from the ongoing heat.

Saturday afternoon into the evening, low chances (30% or less) of thunderstorms return to the forecast as a result of a shortwave ahead of the looming upper level ridge in addition to diurnal heating support. Highs are forecast to quickly rise into the upper 90s once again before convection materializes, with a low chance (25% or less) of some areas in NW AL hitting 100 degrees. A Heat Advisory remains in effect through Saturday. Model soundings show the typical inverted V profile for downbursts, with 1.9" PWAT values (near 90th percentile per BMX sounding climatology) as well as strong MLCAPE (1300 J/kg) and DCAPE (900-1000 J/kg). Stout low level lapse rates (9-10 C/km) are also worth noting to support downbursts and subsequent damaging winds. In addition to PWATS, a low flooding threat will also be supported by slow storm motion as Corfidi upshear values are less than 5 kts. While we are currently barely clipped by a Marginal risk (level 1 of 5), we would not be surprised if the Marginal risk was stretched southwestward into portions of northeastern AL and southern middle TN. Be sure to have multiple ways to get warnings tomorrow afternoon and keep up to date with the latest forecast.

SHORT TERM

(Saturday night through Monday) Issued at 937 PM CDT Fri Sep 4 2026

Thunderstorms should gradually come to an end by the late evening hours Saturday with the loss of diurnal support. However, sub- severe thunderstorms will likely remain in the area through the early morning hours- bringing additional heavy rainfall as well as lightning with a low chance of gusty winds. While our Heat Advisory was slated to end Saturday night, it has now been extended to Sunday night as the Tennessee Valley remains under the influence of an upper level ridge and subsequent above normal temperatures. High temperatures on Sunday are forecast to reach the upper 90s with heat indices up to 109 degrees. A cold front should push through the area Sunday afternoon, bringing slight relief from the heat by Sunday night as low temperatures drop into the upper 60s to lower 70s (as opposed to mid 70s the past several nights). Highs on Monday are still forecast to reach the 90s, however, heat indices should be capped near 100 degrees as a relatively drier airmass shifts southward into the area. Low chances (30% or less) of thunderstorms remain in response to diurnal heating Monday afternoon.

LONG TERM

(Monday night through Friday) Issued at 937 PM CDT Fri Sep 4 2026

Heat will persist through the long term as well. The vast ridge of high pressure that is centered over the Southern Plains and Mid MS Valley will expand eastward to encompass the rest of the Southeast early this week. Mid week, a trough will swing through the southern Canadian prairie provinces dampening the ridge, and sfc high pressure will set up along the Appalachians. This set up could create a CAD expanding into NE AL and portions of Southern Middle TN. If this comes to fruition, adjustments to POPs (slight increase) and temps (slight decrease) would be needed. Regardless, it looks like temps will remain in the 90s throughout the week, which is par for the course this month, but running a tad higher than seasonal norms which is 87-88 degrees. Heat index values will hover around 100 degrees and the NWS Heat Risk will be a level 2 (Moderate Level) for the large majority of us. Remain heat smart: slow down, cool down, stay hydrated and NEVER leave people or pets in vehicles.

AVIATION

(00Z TAFS) Issued at 617 PM CDT Fri Sep 4 2026

VFR conditions are forecast overnight into Saturday morning. Saturday afternoon into the evening, a PROB30 group was added at both sites into MVFR due to low thunderstorm chances potentially causing lowered visibilities and ceilings.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Heat Advisory until 8 PM CDT Sunday for ALZ001>010-016.

TN...Heat Advisory until 8 PM CDT Sunday for TNZ076-096-097.