textproduct: Huntsville

KEY MESSAGES

Updated at 1038 AM CDT Thu Aug 20 2026

- There is a low chance for strong to severe storms this afternoon into the evening with the main threat being damaging winds, along with heavy rainfall, frequent lightning, and perhaps some small hail.

NEAR TERM

(Rest of Today and Tonight) Issued at 1038 AM CDT Thu Aug 20 2026

The complex of showers and storms to our north in Tennessee that brought a few showers/storms to our TN counties and into north- central AL earlier this morning continues to dwindle and move east. However, most of this activity remains to our north. There has been some development of a few showers and storms to our northwest over the past hour. This will be something to watch over the next few hours, but Hi-Res guidance suggests that these will wane and not be the main concern. As an upper shortwave trough moves into the Ohio and Tennessee valleys today, the main show in the form of a sort of broken line of showers/storms is expected this afternoon. Most guidance shows this activity starting around 2PM and moving from northwest to southeast over the local area through this evening.

Taking a look at bulk shear, model values range between 20-30 knots with ample instability (1800-3000 J/kg CAPE). DCAPE values exceed 1000 J/kg as well, so damaging winds will be a main hazard with any strong to severe storms that develop. This coincides with an area-wide Marginal Risk of severe storms from SPC. However, we are not as confident when it comes to the hail threat because of this morning's observed and model soundings giving between 14-15 kft for the freezing level. Ultimately, hail can't be ruled out entirely but it doesn't seem to be the bigger threat (like damaging winds). Additionally, our PWATs generally range between 1.75-2.0 inches today, with values greater than 2 inches in some locations later today into this evening. With the 75th percentile (compared to BMX sounding climatology) around 1.8 inches and the 90th percentile right around 2 inches, this means that showers and storms will be efficient rainfall producers today which could result in at least nuisance flooding. Overall, stay weather aware today and take shelter if a warning is issued for your location! Lightning is also hazardous, so if you're outside and you hear thunder or see lightning, head indoors! If you encounter flooded roads, turn around, don't drown!

As for temperatures, it will be warm today with highs topping out in the mid to upper 90s. NE AL and portions of southern middle TN may be a touch cooler, in the lower to mid 90s. Overall, thinking that the NBM is a bit too bullish when it comes to dew points through the day. Most other guidance suggests values generally between upper 60s to lower 70s (even perhaps the mid 70s in a few spots). Decreasing our forecast dew points a bit did temper our heat index values down to between 100-105 degrees for most of the local area as well. More urban spots like Huntsville or Muscle Shoals may see values closer to 105-106 degrees though. Even with this in addition to NWS HeatRisk at the Major category (level 3 of 4) for a portion of the area (mostly north-central Alabama), not confident in any heat products due to the low to medium (20-50%) chances of showers and storms this afternoon. This will be monitored. Regardless, please practice heat safety. Stay hydrated and take frequent breaks in the shade if you work outside or have outdoor activities.

For tonight, while some shower and storm activity may linger into the overnight period, the severe threat is expected to largely end around 9PM this evening. The concern then turns to chances of patchy to areas of fog (20-40%) where there are breaks in the clouds tonight. Not expecting widespread dense fog, but with light to calm winds, there is the potential for at least patchy fog in river valleys, sheltered locations, near bodies of water, and for spots that receive rainfall today. Lastly, expect lows to dip into the upper 60s to lower 70s.

SHORT TERM

(Friday through Saturday) Issued at 1038 AM CDT Thu Aug 20 2026

There is a low chance (10-15%) of some lingering showers/storms during the day on Friday, but no severe weather is anticipated. Dry conditions then return on Saturday as an upper ridge over the central CONUS builds eastward into the ArkLaTex and Southeastern states. In addition, highs are expected to max out in the upper 80s to lower 90s each day. Fortunately, the NWS HeatRisk decreases to be in the Minor category, along with heat index values only reaching the 90s. Thus, a slightly cooler weekend is on tap for north Alabama and southern middle Tennessee by the weekend. Enjoy!

LONG TERM

(Saturday night through Wednesday) Issued at 1010 PM CDT Wed Aug 19 2026

The long term should remain fairly tranquil under the influence of an upper level ridge and subsequent sfc high pressure from the north. Highs during this time are forecast to continue to reach the 90s with heat indices up to 100 degrees, which will keep us without any heat products on the table. One thing to watch will be a shortwave and subsequent sfc low with an accompanying frontal boundary that may clip the western portion of our area on Monday into Tuesday. For now, have kept PoPs aligned with blended guidance due to uncertainty in the evolution and speed of this front. Therefore, low chances (20% or less) of rain exists Monday into Tuesday. If you have outdoor interests early next week, be sure to check back in for forecast updates.

AVIATION

(18Z TAFS) Issued at 1235 PM CDT Thu Aug 20 2026

There remains a low to medium chance (20-50%) of showers and storms this afternoon through this evening. Some of these may become strong to severe with damaging winds the main hazard, but heavy rain, frequent lightning, and hail will be threats as well. This activity is expected to bring lower CIGs and VIS to the terminals in the heavier showers/stronger storms generally between 21Z-3Z or so as a broken line moves through. Showers and storms will then decrease through late evening (as well as the severe threat), with the potential for some lingering showers overnight. Low to medium chances (20-40%) of fog will then become the concern late tonight into early Friday morning. Not anticipating dense fog at this time, but this will be monitored in case clouds clear out a bit more than forecast. VFR conditions should return to both sites by mid to late morning on Friday. Otherwise, outside of any storms, westerly winds around 5 knots or so will be common this afternoon. Winds then decrease to be light to calm tonight.

HUN WATCHES/WARNINGS/ADVISORIES

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