textproduct: Huntsville

KEY MESSAGES

Updated at 326 AM CDT Tue Aug 18 2026

- Low shower/thunderstorm chances return this afternoon over northwest Alabama.

- Low to medium shower and storm chances return tonight and again Thursday, with a low chance (~10%) of stronger storms Thursday afternoon.

- Heat Risk will decrease through the week, from Moderate values (level 2 of 4) today and Thursday, down to Minor values (level 1 of 4) late in the week.

NEAR TERM

(Today and Tonight) Issued at 326 AM CDT Wed Aug 19 2026

A cold front that moved southward across the Tennessee Valley last night has become stationary, oriented approximately from central Arkansas, to north of Montgomery, to the South Carolina coast. Convection that occurred well south of Birmingham yesterday has faded, with just thinning cirrus over the Deep South. A cooler airmass is noticeable with current temperatures in the mid 60s to around 70 (compared to mid/upper 70s yesterday). Although cooler, dewpoint values were near or matching drybulb temperatures. Thus there is a risk of late night and early morning fog formation (which will become more of an issue as we go into the late summer and beyond), as days become shorter.

Another item of concern is a thunderstorm complex over Missouri moving bit to the south of due east. Outflow boundaries from it should propagate across this region late this morning and in the afternoon. Despite the front being south of us, generally sunny skies will result in temperatures rising into the low/mid 90s. Moisture values will also increase with precipitable water amounts of 1.7" to 1.9" this afternoon over our western areas. This brings heat indices back into play, as they rise into the upper 90s to 107 over parts of NW Alabama. Most of the models did not catch the shower potential, but the SPC view of the HREF did. So have added low PoPs showers/thunderstorms across NW Alabama this afternoon. Storms that develop could become strong to marginally severe, with strong outflow downburst-type wind gusts the main threat. The mixing of the lower levels from daytime heating, and more clouds with rain chances should keep areal coverage of heat too low to warrant a Heat Advisory this go around.

Showers should fade in the early evening with a loss of daytime heating. Yet another disturbance and thunderstorm complex nearing from the west will bring lower end rain chances late tonight into Thu morning. Stayed with the blends output, which keep the showers closer to the TN/AL border. These storms could become strong should they move more to the south, with strong winds and heavy downpours the primary threat.

SHORT TERM

(Thursday through Friday)

Issued at 1006 PM CDT Tue Aug 18 2026

Of the first few days of the forecast package, Thursday looks like it could be the most interesting, with a low-end chance for a few stronger storms Thursday afternoon. While not officially outlooked yet, a shortwave pinwheeling into the area from the NW yet again will spark shower and thunderstorm activity Thursday afternoon. During this time, modest instability and ever-so-slightly bulk shear values increase ahead of the feature during peak daytime heating, which may allow for stronger storms to develop. Confidence is not high at this point in time in seeing severe storms, but if Monday was any indicator, it's definitely an option on the table. We'll continue to watch this timeframe for any forecast shifts/tweaks in the placement of the shortwave or the increasing/decreasing bulk shear values that may aid in better organization of convection during this time.

A frontal boundary will sag southward through the area on Friday, with low to medium chances for showers and storms once again. Highs Friday afternoon will top out in the upper 80s to low 90s.

LONG TERM

(Friday night through Tuesday) Issued at 1006 PM CDT Tue Aug 18 2026

Dry conditions in the wake of the frontal boundary will prevail this weekend, which will be a far cry from this time last weekend when we saw Heat Advisory/Extreme Heat Warning criteria across the Southeast. Heat Index values this weekend won't even crack the century mark, topping out a few degrees on either side of 95F. Rain returns by Tuesday, but otherwise seasonable temperatures will prevail during this time with daytime highs in the lower 90s and morning lows in the middle 60s (with even a few pixels of lower 60s in sheltered valleys of NE AL)!

AVIATION

(06Z TAFS) Issued at 1238 AM CDT Wed Aug 19 2026

VFR weather currently prevailed across the greater TN Valley. Patchy fog however was forming over parts of NE MS. More of this fog could develop as we go into the overnight with MVFR or lower VSBY reduction. Any fog that forms should dissipate shortly after daybreak. VFR conditions are expected with light winds becoming N-NE around 5kt in the late morning and afternoon. After local midnight Wed night, late night/early morning convection could impact the terminals; it will be covered in future issuances.

HUN WATCHES/WARNINGS/ADVISORIES

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