textproduct: Huntsville

KEY MESSAGES

Updated at 1149 AM CDT Sun Sep 20 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 between 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

(Rest of Today and Tonight) Issued at 1145 AM CDT Sun Sep 20 2026

A upper level trough axis extending southward from the Ohio Valley continues to be seen in satellite imagery over extreme NW Alabama slowly moving east. Along and ahead of this feature, forcing associated with it should be the impetus for any isolated to scattered convection as instability builds through the day. Models differ on the strength of theta-e lapse rates aloft. DCAPE and mixed layer CAPE remains high in forecast guidance. Not sure if we might see a few stronger microbursts given the uncertainty of steeper theta-e lapse rates aloft. If any stronger storms occur, damaging microburst winds would be the main concern. Expect activity to weaken and dissipated like yesterday by the late afternoon hours. We had morning fog in the valley areas of northeastern Alabama per satellite imagery). Given the higher chances of additional convection would be in those same areas later today, expect fog development late tonight into the daybreak hours on Monday. Low temperatures should again be in the upper 60s to lower 70s.

SHORT TERM

(Monday through Wednesday) Issued at 1015 AM CDT Sun Sep 20 2026

Monday and Tuesday still look more active as a stronger longwave trough axis and associated cold front push east towards the Tennessee Valley area during that period. Shear still looks very weak, but theta-e lapse rates steepen. Strong forcing ahead of the trough axis/surface front and a very unstable atmosphere (3000-4000 J/KG) should provide ample impetus for scattered to widespread convective development, especially near and east of the I-65 corridor. With DCAPE around or over 1000 J/KG along with theta-e lapse rates around 30 degrees, a threat for strong to severe storms (producing damaging microbursts) looks reasonable. This should not be a washout by any means, but with PWATS around 1.8 inches and slow movement of storms expected, some locally heavier rainfall amounts could occur with slow moving or stationary storms. Highs should be tempered more by cloud cover and convective activity. That being said, highs will still likely climb into the 93 to 97 degree range on Monday. Some very localized heat index values around 105 could be meet in SE portions of Madison county or northern Marshall county, but do not look widespread enough for the issuance of any Heat Advisory products. With the front moving into northern Alabama on Tuesday and increasing cloud/convective trends expected, highs should be a bit cooler only climbing into the upper 80s to lower 90s. Heat index values should remain between 95 and 104 degrees one more day.

LONG TERM

(Tuesday night through Saturday) Issued at 1015 PM CDT Sun Sep 20 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 (30-50%) for showers and storms are expected through Tuesday night.

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

(18Z TAFS) Issued at 1149 AM CDT Sun Sep 20 2026

VFR conditions are expected throughout the TAF period. Though light winds are expected overnight, chances of appreciable fog development are too low to include at either terminal around daybreak on Monday. -TSRA chances may need to be introduced after 18Z on Monday.

HUN WATCHES/WARNINGS/ADVISORIES

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