textproduct: Huntsville

KEY MESSAGES

Updated at 1014 PM CDT Sun Jul 19 2026

- A Heat Advisory will be in effect for most of the Tennessee Valley for the Monday through Tuesday timeframe.

- Moderate (Level 2/4) to Major (Level 3/4) Heat Risk will build into the Tennessee Valley through the middle of the week, with peak heat index values between 100 to 109 degrees likely in some locations Monday and Tuesday.

- Daily thunderstorm chances will continue into early next week. A few storms could become strong to marginally severe Tuesday. Gusty to damaging winds, frequent lightning, and locally heavy rainfall will be the main threats.

NEAR TERM

(Rest of tonight and Monday) Issued at 1014 PM CDT Sun Jul 19 2026

Numerous showers and thunderstorms that earlier impacted much of the Tennessee Valley have for the most part dissipated and/or moved south of the area as of the early night-time. Otherwise under a mix of mostly cloudy to overcast skies, 10 PM temperatures have cooled into the 70s, after earlier reaching highs from the mid 80s to mid 90s, with rainfall amounts over 2" in a few spots. With plenty of residual moisture, even in spots that have not received wetting (> 0.10") rainfall, expect muggy conditions for the overnight with lows only cooling into the lower 70s, with a few spots only into the mid 70s. Thanks to light winds and "clear" skies (thinning higher altitude clouds), there is a risk for late night fog formation, especially in/near those more fog favored spots, and in locations that received wetting rains.

Newer model guidance coming continued to suggest lower rain chances for the start of a new work week. A system that in part could intercepting moisture from the Gulf region is Tropical Depression #2 located about 180 miles south of Panama City. This system is expected to take a NW, then west track towards the Mississippi Bayou into Tue. This tropical system should have little impact over this region into the mid week. Under mainly partly cloudy skies, heat could become a problem on Monday. Outside of shower activity, high temperatures should rise into the low/mid 90s. Corresponding heat index values should range from the upper 90s to 107. Areas covered by 105 degree or higher heat indexes are sufficient to put out a Heat Advisory starting Monday at 10 AM for all areas except DeKalb County. Area residents are urged to take precautions regarding the heat and humidity.

Scattered afternoon shower and thunderstorm chances do remain despite lower moisture content than today. Storms that do form should be "sub-severe" but will be capable of producing strong gusty winds, frequent lightning strikes, and torrential downpours. Am expecting shower coverage to remain isolated to at times scattered in coverage.

SHORT TERM

(Monday night through Wednesday) Issued at 1014 PM CDT Sun Jul 19 2026

As has been the case the past few nights, showers that form should fade as we go into Mon night. We cannot rule out patchy later night fog in areas that receive wetting rainfall, as well as fog favored spots. Another muggy and humid night with lows in the low/mid 70s. The milder lows in the mid 70s would help set the stage for more heat issues Tue. Inland deep moisture transport from the Gulf of America should be limited by the tropical entity, thus with lower rain chances, hot conditions will again rule. High temperatures should warm into the low/mid 90s, with heat index values from the upper 90s to 109 degrees. Will have the Heat Advisory continuing into early Tue evening.

Sultry conditions are expected Tue night, as low temperatures cool only into the mid 70, with some upper 70s in the more urbanized heat islands. Depending upon how much of the area will be impacted by clouds and showers in later forecasts, the heat advisory may be needed for some of the area Wed. Very warm upper ridging that was positioned over the central High Plains earlier in the week, should weaken somewhat and build more towards the SW. While this occurs, a system moving in the main westerlies over Canada will induce more troughing from the Great Lakes to the Mid Atlantic in the mid week. This will help bring a surface cold front towards the forecast area on Wed. Lift provided by the front, along with medium to high shower and thunderstorm chances (greater rain chances east) will help provide relief from the heat. Highs should be a tad cooler, from the mid/upper 80s east to low/mid 90s west, with heat index values from the mid 90s to 105 in a few spots. Conditions should cool down a little more Wed night with lows falling into the upper 60s to around 70.

LONG TERM

(Wednesday night through Sunday) Issued at 1014 PM CDT Sun Jul 19 2026

The passage of a cold front on Wednesday will mark the start of the long term forecast with slightly lower temps and dew points. Highs through the long term period will be relegated to the low 90s with dew points dropping back to the high 60s to low 70s. The passage of the cold front will mark a pattern change with a troughing east/ridging west regime setting up through the long term forecast. As such, we will find ourselves solidly in NW flow as we head into the weekend and into early next week. This will keep medium rain chances in the forecast as several shortwaves ripple along the base of the trough. This set up does favor MCSs dropping south along the base of the trough, potentially into our area. As the set up draws nearer, we will continue to evaluate MCS potential and any increased threats for severe weather or flooding.

AVIATION

(06Z TAFS) Issued at 1241 AM CDT Mon Jul 20 2026

High altitude clouds from earlier convection were fading as they moved southward in a northerly flow. Thus skies overnight should become mostly clear with mainly high level clouds. Some of the models redevelop low/mid level clouds in the overnight. Patchy fog development may occur over and near areas that received wetting rainfall on Sun. VSBY reductions to IFR (less than 3SM) may occur locally. The formation of more lower clouds beforehand could hamper fog formation. Fog that forms should fade shortly after sunrise, with VFR conditions returning shortly thereafter. Daytime heating could result in isolated to scattered convection forming in the afternoon. Given low confidence, have maintained VCSH for much of the afternoon. Any shower activity should fade shortly after sunset. Light winds overnight will become light from S-SW in the late morning and afternoon, then light again after dusk.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Heat Advisory from 10 AM this morning to 8 PM CDT Tuesday for ALZ001>009-016.

TN...Heat Advisory from 10 AM this morning to 8 PM CDT Tuesday for TNZ076-096-097.