textproduct: Huntsville

KEY MESSAGES

Updated at 419 AM CDT Sun Sep 6 2026

- A Heat Advisory remains in effect through 8 PM this evening due to a Major Heat Risk, and afternoon heat indices rising up to 105-109 degrees in portions of the forecast area.

- A risk of strong to severe thunderstorms is forecast for much of the Tennessee Valley today. Strong to damaging wind gusts are the main threats posed by the stronger storms.

- Not as hot high temperatures continue from Labor Day into the late week.

NEAR TERM

(Today) Issued at 419 AM CDT Sun Sep 6 2026

A somewhat of busy overnight continued, as isolated to scattered showers and thunderstorms impact portions of the Tennessee Valley. This convection was forming in an unstable region aloft, and from interaction of numerous remaining outflow boundaries from previous convection. This elevated instability was producing moderate mid- level lapse rates of near 6C/km especially over Middle Tennessee, along with mix layer CAPES of 1500-2000 J/kg. This activity was heading southward around 10 mph. In a very moisture environment with precipitable water amounts of 1.8 to 2", some locally heavy amounts of rainfall have occurred (including from Sat). A few mesonet sites have recorded local totals over 1.5" in spots from west of Winchester and around Huntsville. MRMS was showing spotty maxima in those locations above, and SE of Decatur and west of Cullman. Most model guidance has the convection winding down as we near daybreak. Muggy conditions will continue, with lows only falling into the low/mid 70s. Given humid conditions, some patchy late night fog could occur, especially in those normally fog prone locations, as well as places that received recent rainfall.

One more hot day is forecast to start out a new week. High temperatures should soar back into the mid/upper 90s (cannot rule out an isolated 100F high in the hottest spots). Dewpoints staying in the low/mid 70s will produce heat index values from 105-109F, thus the Heat Advisory continues through 8 PM this evening.

A frontal boundary located from the northern High Plains, across Missouri and Kentucky, and the Carolinas will move southward across the region today. As a slightly milder airmass filters in, strong daytime heating and resultant instability will result in the development of additional showers and thunderstorms. With a moisture laden environment in place, daytime heating will produce higher instability, along with an airmass change as slightly drier air filters in. Thus some of the storms could become strong to severe in intensity, with damaging outflow wind gusts the main threat. Frequent lightning and heavy downpours are expected as well. Flash flooding is minimal, especially if heavy rain impacts an area that already received recent heavy rainfall.

SHORT TERM

(Tonight through Tuesday) Issued at 955 PM CDT Sat Sep 5 2026

The short term period will be driven by the upper level ridge as it shifts slightly westward to begin the work week then quickly returns eastward, bringing continued above normal temperatures to the Tennessee Valley. During this time, high temperatures are forecast to reach the upper 80s to mid 90s (with warmer temperatures remaining in NW AL) and heat indices up to near 100 degrees. These relatively cooler (than the past week) temperatures will keep heat products off the table since we will be below criteria, however, be sure to continue practicing heat safety to avoid heat illness if spending time outdoors.

LONG TERM

(Tuesday night through Saturday) Issued at 955 PM CDT Sat Sep 5 2026

As the upper level ridge remains the main influence over the area through the long term, there will also be another feature to watch. As an upper level shortwave and subsequent low pressure system shift eastward north of the Great Lakes, a weak ridge will develop ahead of this in the northern Appalachian region and bring subsequent sfc high pressure. In turn, weak CAD will advect into the eastern portions of the area, which will likely set up a differential heating boundary by early to mid week and allow low chances of thunderstorms (30% or less) each afternoon. This will be dependent on where the sfc high officially sets up. Otherwise, mostly dry conditions are forecast with continued high temperatures in the low to mid 90s. Beyond the long term, the Climate Prediction Center keeps us in an area for likely above normal temperatures for the 8-14 day period. Therefore, relief from this heat is not currently in sight.

AVIATION

(06Z TAFS) Issued at 1135 PM CDT Sat Sep 5 2026

VFR conditions continue through the TAF period at both sites with a low chance (15%) of shower or thunderstorm development at KHSV over the next 1-2 hours. This has not been added to the official TAF due to very low confidence in this affecting the terminal. Otherwise, a low chance of patchy fog exists during the early morning hours on Sunday. Confidence remains low in this affecting the terminal.

HUN WATCHES/WARNINGS/ADVISORIES

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

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