textproduct: Huntsville

KEY MESSAGES

Updated at 905 PM CDT Mon Jul 20 2026

- A Heat Advisory is in effect for most of the Tennessee Valley through Tuesday at 8 PM.

- 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 most locations today and Tuesday.

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

NEAR TERM

(Rest of tonight and Tuesday) Issued at 905 PM CDT Mon Jul 20 2026

Showers and storms have greatly waned now that the sun has set. Under high pressure influence, winds will calm overnight. Calm winds paired with low dew point depression will allow for patchy fog formation through the early morning hours.

As we head into the day tomorrow, mid level ridging will push east into the TN Valley. This will support temperatures peaking a degree or two hotter than today to around 95 degrees. Additionally, the eastward motion of the ridge will work to suppress cloud formation and rain chances leaving dry and clear conditions Tuesday afternoon. With dew points remaining in the mid 70s, heat will continue to be a concern with Tomorrow afternoon looking like the hottest day of the week. Heat Indices look to soar above 105 with heat risk reaching level 3/4 for a majority of the area. As such, a heat advisory remains in effect for everywhere except Dekalb county (where elevation looks to keep things a few degrees cooler) through 8 PM Tomorrow. Please make sure to practice proper heat safety.

SHORT TERM

(Tuesday night through Thursday) Issued at 905 PM CDT Mon Jul 20 2026

As the sunset, storms will likely be on the horizon to our north along an approaching cold front. Models maintain a later arrival of storms, between 10 PM - 12 AM. Fortunately, the later arrival will allow time for instability to erode, leaving only a few hundred J/KG of CAPE by the time storms get here. Models diverge on coverage of showers and storms with some dissipating storms as they arrive and other dragging a broken line of storms through, dissipating as they go. What is consistent is the lack of shear, meaning regardless of the actual coverage of storms, any storms that do make it through will obtain only a low severe threat with the primary hazard being damaging winds.

The actual front looks to push through Wednesday morning, leaving drier and relatively cooler temperatures in its wake. Temps on Wednesday will be relegated back to the low 90s with temps dropping even further on Thursday to the high 80s. Dew points will drop through the day on Wednesday with mid to high 60s dew points in place by Thursday morning. From late Wednesday into Thursday, the aformentioned front looks to stall just to our south. This will keep some post frontal cloud cover through the day on Thursday and also support low rain chances (20-40) in far SE portions of our CWA. Fortunately threats for both severe weather and excessive heat will remain low. However, remaining weather aware and practicing proper heat safety are always good summer practices.

LONG TERM

(Thursday night through Monday) Issued at 905 PM CDT Mon Jul 20 2026

The general upper level setup will consist of a ridging west and troughing east pattern over the greater North American domain. This pattern was being kept in place by Omega-style upper blocking over the northern Pacific basin. At the beginning of the extended, upper troughing will be in place off of the west coast (the eastern anchor of the upper block), with strong upper level ridging situated over the southern Great Plains. A passing upper low over the central Ontario and Quebec region will deepen, and help amplify upper troughing from the eastern Great Lakes to northern Florida. This will place the Tennessee Valley in a WNW-ESE flow from the late week into early next week.

A northwesterly upper level flow across this area, especially if it is disturbance laden, is known for bringing showers and thunderstorms to the Valley. Convection in these regimes can be accompanied by strong winds. For this area, a few complications to that simplistic view. First, a cold front should be south of the area by late Thu. Moisture from Tropical Storm Bertha should be streaming back to the NE, with some of it impacting the area Fri into Sat. Along with lower level tropical moisture, some of the extended guidance was suggesting that upper level support moving across the area from late Fri into Sun could bring more thunderstorms to the area. It is way too early to discern if this convection could become more significant, given much model uncertainty this far out. With a main synoptic front to our south and with some shower/storm chances, daily high/low temperatures should trend a bit milder, with highs Fri/Sat in the mid 80s to around 90. Warmer conditions look return for the start of the new week, with highs from the upper 80s to lower 90s Sun, and low/mid 90s next Mon. Lows Thu night should range in the mid/upper 60s, with mainly lower 70s for the Fri - Sun night period.

AVIATION

(00Z TAFS) Issued at 552 PM CDT Mon Jul 20 2026

Showers and storms will wane after sunset with VFR conditions taking over for the remainder of the night. There is a low chance of fog tomorrow morning however confidence is currently too low to include it in the TAF. Come sunrise, winds will pick up slightly from the south with dry VFR conditions prevailing through the remainder of the TAF period.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Heat Advisory until 8 PM CDT Tuesday for ALZ001>009-016.

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