textproduct: Huntsville

KEY MESSAGES

Updated at 1026 AM CDT Fri Sep 11 2026

- Low-medium chances for showers and storms this afternoon and evening, increasing to medium-high chances Saturday. A low chance of severe storms is forecast this afternoon, bringing a risk of gusty to damaging winds.

- NWS Heat Risk will remain in the Minor to Moderate category throughout the forecast period.

NEAR TERM

(Tonight) Issued at 144 PM CDT Fri Sep 11 2026

Weak disturbance over the Gulf region will continue to move northward this afternoon, interacting with a very moist air mass and generating clusters of showers and thunderstorms across much of central Alabama and eventually the Tennessee Valley. Observational data still shows some steep low-level lapse rates (8 to 8.5 C/km), but DCAPE values are a bit lower than other days (500-600 J/kg). All this to say, we could still see a few strong to perhaps a marginally severe storms this afternoon/evening (2-8 PM), but the overall threat is low. Poor shear values will lead to disorganized, pulse convection -- with locally heavy downpours the primary concern with this activity. Hi-Res guidance is a little all over the place for tonight, but generally does shows a dissipating trend by the late evening. Still think that some low to medium (30-50%) coverage of showers and sub-severe thunderstorms may be in the cards overnight along residual outflow boundaries. For this reason, we have tweaked PoPs up slightly (30-60%) after Midnight.

Previous Discussion:

The Tennessee Valley sits between two features of note today. The first more prominent shortwave trough is positioned over the mid- south with convection ongoing to the north and west of the CWA.

Another more subtle shortwave is analyzed near southwest AL, and is sparking storms across the Gulf coast. The more prominent trough will slowly move toward our area throughout today and into tonight. This will cause the southern disturbance to pivot northeast toward our area providing lift for showers and thunderstorms.

PWATs of 2.13 inches per the 12Z BMX sounding are near record values for this time of year. We expect rain chances to increase across the area this afternoon and coverage should peak in the late afternoon and early evening. Storm motions are expected to be slow from southwest to northeast and given the high moisture content, the primary concern today and tonight is flood potential with the WPC placing our entire area under a marginal risk for excessive rainfall. With MUCAPE expected to be ~1000 J/kg and some instability above the freezing level, lightning will be another threat along with wind gusts potentially reaching 40-50 mph in the strongest storms. Some instability will persist into tomorrow morning. Thus we expect rain chances to continue through the overnight.

Regarding temperatures, current highs are forecast to be in the 90-95 degree range. These values could be a little high if impact from precipitation or clouds occurs earlier in the day. Overnight lows are expected to be in the upper 60s and low 70s.

SHORT TERM

(Saturday through Sunday) Issued at 1026 AM CDT Fri Sep 11 2026

A front will move south and east into the Tennessee Valley on Saturday, serving as a focus for additional rounds of showers and thunderstorms in this very moist environment. The main threat on Saturday will pivot away from gusty winds and a low severe threat to locally heavy rainfall and a low flash flooding threat. This will be due to PWATs around 2", slow storm motions, and the mean flow being more or less parallel to the frontal boundary. All this will result in medium to high chances (60-90%) of showers and thunderstorms, peaking in the afternoon. The highest coverage will likely favor locations along and near the boundary itself, meaning that adjustments may be needed to PoPs should this feature setup a little further north or south than anticipated. Still, those with outdoors plans should anticipate the potential for showers/storms at some point during day.

Storms will wane by the evening hours and much drier conditions are forecast Saturday night into Sunday with the boundary sinking southward. However, the air mass won't modify all that much and with dewpoints in the 70s another warm/humid day will be on tap for Sunday. Highs in the upper 80s to mid 90s and heat index values between 96-103 degrees will be common, creating Moderate (Level 2/4) heat impacts.

LONG TERM

(Sunday night through Thursday) Issued at 808 PM CDT Thu Sep 10 2026

As we start the following work week, the upper level pattern shows a large amplitude ridge over most of the central and eastern US. With high pressure situated underneath the ridge, expect hot and humid conditions to continue through the middle of next week. Afternoon highs each afternoon will rise into the low to mid 90s with overnight lows in the upper 60s to lower 70s. With dewpoints in the lower 70s, heat indices are forecast to top out between 98-104F. This is just below Advisory criteria, but regardless NWS HeatRisk remains level 2 out of 4 (Moderate) through the end of the long term period. Outside of the heat, there is a low chance of an afternoon shower or thunderstorm Monday through Thursday.

AVIATION

(18Z TAFS) Issued at 1224 PM CDT Fri Sep 11 2026

Clusters of showers and storms will develop and approach the Tennessee Valley this afternoon/evening and periods of the overnight hours. While VFR conditions will be the prevailing flight category at each terminal through the period, have included a TEMPO between 22-02z and a PROB30 between 02-08z to account for localized MVFR to IFR conditions. Lower ceilings may settle in late tonight into early Saturday morning in wake of these storms, before clouds scatter out late in the period.

HUN WATCHES/WARNINGS/ADVISORIES

AL...None. TN...None.