textproduct: Huntsville

KEY MESSAGES

Updated at 1141 AM CDT Mon Jul 27 2026

- Heat Advisory and Extreme Heat Warning in effect for portions of the TN Valley through 7PM Tuesday.

- A cold front will bring additional thunderstorms to the region Tuesday afternoon/evening, with coverage highest in the east. A a few strong-severe storms may occur during this timeframe.

- A drier airmass will encompass the region from Wednesday- Friday, but chances for showers and some thunderstorms will increase once again this weekend.

NEAR TERM

(Rest of Today and Tonight) Issued at 1141 AM CDT Mon Jul 27 2026

Showers and thunderstorms have moved out of the TN Valley leaving us with mostly sunny to partly cloudy skies at this hour. This will give way to temperatures running up into the mid 90s in NW AL and the lower 90s in NE AL. With plenty of moisture in place, heat index values will climb to 103-112 degrees across the TN Valley. Current forecast trends and observations led us to expand the Heat Advisory eastward to include NE AL and upgrade portions of NW AL (Lauderdale, Colbert, and Franklin Co) to an Extreme Heat Warning. These products will go through 7pm Tuesday, however the Extreme Heat Warning may need to be expanded eastward to the I-65 corridor for Tuesday afternoon if trends persist.

There may be a shower or two today, due to the heat and moisture in place, but we don't have any good lifting mechanisms in place. The MCS that will dive southward out of the Midwest today is forecasted to miss us to the NE tonight, however will not rule out some showers and thunderstorms brushing Southern Middle TN, maybe into NE AL if it can make it. For this, SPC has a Marginal Risk out for Southern Middle TN to accommodate the threat for strong winds in some of the stronger storms.

SHORT TERM

(Monday night through Wednesday) Issued at 1109 PM CDT Sun Jul 26 2026

Over the course of the short term period, an intensifying mid- level shortwave trough in the northern stream is predicted to travel across the eastern Great Lakes before evolving into a closed low over the northern Mid-Atlantic states that will drift slowly east-southeastward through Wednesday. In the low-levels, a surface low related to the shortwave trough is expected to gradually deepen across NY/PA, with a cold front attached to the low expected to make steady southeastward progress on Monday night and Tuesday. Southwesterly flow in the low-levels will begin to strengthen on Monday night, and although latest guidance from the CAMs indicates that another MCS will track south-southeastward from the Lower Great Lakes into eastern KY/TN, at this point it appears as if this system will bypass our forecast area to the northeast.

However, chances for thunderstorms should begin to increase in our CWFA by mid/late Tuesday afternoon (and continue through the evening hours) as a prefrontal trough/wind shift axis begins to enter the region from the north. Although the coverage of convection should be higher to our north/east (where deep-layer ascent will be augmented by the shortwave trough), it seems reasonable to believe that at least scattered storms will develop as far southwest as northern AL. Very hot temperatures (m-u 90s) and high dewpoints (u70s-l80s) will exist ahead of the wind shift axis, warranting another Heat Advisory and yielding high CAPE of 3000-3500 J/kg. This level of instability, coupled with an increase in NNW flow aloft to 20-30 knots, suggests that damaging winds and frequent lightning will be possible with the strongest cells. Light northerly flow in the wake of the front will begin to advect a drier continental airmass into the region during the day on Wednesday, with only a low chance for a few showers south of the TN River before this occurs.

LONG TERM

(Wednesday night through Sunday) Issued at 1109 PM CDT Sun Jul 26 2026

Extended range guidance from the lastest suite of global models continues to indicate that our forecast area will remain under the influence of moderately strong NNW flow aloft and dry northerly flow at the surface from Wednesday night-Friday. With dewpoints falling into the 60s, overnight lows will respond by dropping to more comfortable levels (m-u 60s), with afternoon highs remaining in the u80s-l90s. However, it appears as if deep-layer moisture will quickly return to the region at some point Friday night/Saturday morning as a compact surface low shifts eastward from the southern Plains into the Lower-MS Valley. Although strong low-level warm/moist advection ahead of the low will contribute to an increase in the coverage of convection across our region, current thinking is that instability will remain low (at least compared to the past couple of weeks) and should limit the overall coverage of thunderstorms. That said, the low-level jet will likely increase considerably ahead of this system, and may yield at least a limited risk for storm organization on Friday night/Saturday. By Sunday, the surface low is expected to weaken and transition into a broad trough across the Gulf Coast states, which should lead to a gradual decrease in the coverage of precipitation across our region.

AVIATION

(18Z TAFS) Issued at 1250 PM CDT Mon Jul 27 2026

VFR conditions are forecast to persist through the TAF period with light W/NW winds. There is a low chance for a few showers and thunderstorms this afternoon but due to low confidence in coverage we did not include any weather mention in the TAFs at this time.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Extreme Heat Warning until 7 PM CDT Tuesday for ALZ001>003.

Heat Advisory until 7 PM CDT Tuesday for ALZ004>010-016.

TN...Heat Advisory until 7 PM CDT Tuesday for TNZ076-096-097.