textproduct: Huntsville

KEY MESSAGES

Updated at 804 PM CDT Sat Sep 19 2026

- Conditions will be favorable for strong-severe thunderstorms each afternoon into Tuesday, with the greatest spatial coverage of storms expected Monday and Tuesday. Locally damaging downburst winds, frequent lightning and heavy rainfall will be the main storm impacts.

- Hot temperatures will continue into Tuesday, with highs in the 90s each day accompanied by heat indices up to around 100-104 degrees.

- A slightly cooler and drier airmass will arrive late in the forecast period, with highs dropping back into the 80s mid week.

NEAR TERM

(Today) Issued at 212 AM CDT Sun Sep 20 2026

Heat will persist again today. Yesterday, we hit 100 degrees at HSV and MSL! That tied a record at MSL and missed the record by one degree at HSV. Daytime highs today will range from the lower 90s in higher elevations to the mid/upper 90s elsewhere. The HeatRisk is Moderate (level 2/4) for most of us with a few locations seeing Major (level 3/4). Heat index values will remain below advisory level of 105 degrees today, thus the Heat Advisory was not extended into today.

This morning, some of us could see patchy fog, especially for those that received rainfall yesterday. The Nighttime Microphysics RGB shows fog starting to funnel into the valleys, and expect that to continue over the next few hours. Today we will be on the eastern edge of an upper level ridge with a convergence axis between it and a meandering upper level low over FL located off to our east. There is where you will find greater coverage of showers and thunderstorms with just a low chance (20%) for the TN Valley this afternoon into early this evening. With PWATs ~1.7", DCAPE ~1,100 J/kg, and MLCAPE ~1,500 J/kg, locally damaging wind gusts from downbursts are possible within stronger storms. The steering flow is also very weak so storms will be moving slowly so heavy rainfall is also a concern. With coverage expected to be low, SPC has kept us out of the Marginal Risk (level 1/5) at this time. Regardless, it will be hot and remain weather aware throughout the day. Be heat smart: slow down, cool down, stay hydrated and never leave people or pets in vehicles.

SHORT TERM

(Sunday night through Tuesday) Issued at 804 PM CDT Sat Sep 19 2026

The primary talking point in the short term period is a low chance of strong to severe storms on Monday during the afternoon into the evening hours due to another threat of downburst winds ahead of an approaching cold front. The Tennessee Valley is currently outlooked in a Marginal risk (level 1 of 5) for severe weather from SPC, whose discussion specifically mentions MLCAPE of 1500+ J/kg and PWATs of around 1.75" (near 90th percentile sounding climatology per BMX) bringing a threat of wet microbursts. Be sure to keep an eye on the latest forecast and have multiple ways to get warnings leading into Monday afternoon.

Otherwise, heat continues to be a concern through the short term as an upper level ridge continues to impact the Tennessee Valley from the west- bringing above normal temperatures. On the bright side, due to atmospheric mixing, heat indices will be slightly cooler than the past several days (reaching 100-104 degrees). In turn, we have allowed our Heat Advisory to expire this evening rather than extend it in time. While there is a low chance of isolated areas reaching 105 degree heat index temperatures (especially urban areas), it will not be widespread enough to warrant the continuation of the Advisory. We continue to urge everyone to stay hydrated and seek shade when outdoors during the hottest part of the day.

LONG TERM

(Tuesday night through Saturday) Issued at 804 PM CDT Sat Sep 19 2026

The long term forecast period will be characterized by a welcomed pattern change. An upper level trough digs down across the Midwest towards the Southeast during the middle of the week. This will push a cold front through the area Tuesday night through Wednesday and as a result, low to medium chances (30-60%) for showers and storms are expected. As the upper level trough axis shifts to our east, northwest flow begins to advect in a noticeably cooler and drier airmass bringing some much needed relief from the heat. We begin to really feel the drier air late Wednesday night into Thursday as dewpoints fall into the lower 60s. Afternoon highs Thursday through Saturday are forecast to only rise into the low to mid 80s with overnight lows in the upper 50s to lower 60s.

AVIATION

(06Z TAFS) Issued at 1219 AM CDT Sun Sep 20 2026

VFR conditions will prevail through the TAF period at KHSV and KMSL. There is a low chance that patchy fog could affect the terminals before daybreak, but confidence is too low to include it at this time. There is also a low chance for showers and thunderstorms this afternoon but coverage is too low to include it as well. Will monitor for any needed adjustments, however for the moment, amendments are not scheduled due to a national issue with receiving METAR data.

HUN WATCHES/WARNINGS/ADVISORIES

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