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KEY MESSAGES

Updated at 254 AM CDT Tue May 26 2026

- A Flood Watch for Flash Flooding is in effect through 10 PM Tuesday for Cullman, Morgan, Madison, Jackson, Marshall and Dekalb counties.

- Medium to high chances for showers and thunderstorms continue across the Tennessee Valley into the weekend.

NEAR TERM

(Today) Issued at 254 AM CDT Tue May 26 2026

Showers continue to develop and lift northward across the TN Valley at this hour. This is due to a vort max moving through the eastern flow of the anchored upper-level low in the ArkLaTex and the tropical like airmass we remain in. The associated sfc low remains in the Lower MS Valley with a stationary front draped from there on up into the OH Valley. Have not seen any lightning come from this batch of showers, but have seen heavy downpours create visibility reductions.

The Flood Watch for Flash Flooding remains in effect for Cullman, Morgan, Madison, Jackson, Marshall and Dekalb counties until 10 pm tonight. Most of the forecast area has received over an inch of rainfall over the past 48 hours, with an axis of 3-4" that stretches from Jackson, SE Madison, western Marshall and a large portion of Cullman Co...and that's just the past 48 hours, not even an event total. As you can imagine, locations in the Flood Watch have a lower Flash Flood Guidance with an hourly value of 1-1.5" compared to ~1.75-2" elsewhere. Will have showers with some thunderstorms once again today. Will start off with low chances this morning and increasing through the day, with the the greatest coverage found in the afternoon hours. PoPs this afternoon will range from the low chances of 20-40% west of I-65, to 50-80% east of I-65. Southerly winds will gust towards 15 mph this afternoon and highs will only reach the upper 70s to lower 80s.

Remember: if you see water over the roadway or walkway, Turn Around, Don't Drown.

SHORT TERM

(Tuesday night through Thursday) Issued at 1120 PM CDT Mon May 25 2026

The forecast should take on more of a diurnal trend (this one with higher rain chances afternoon/evening) as we go into through the midweek. Another muggy night is expected Tuesday night, with lows in the mid 60s. PW moisture of 1.6" to 1.7" is expected Wednesday, bringing more potentially heavy downpours. With more clouds and decent rain chances of 60-80%, high temperatures should range in the low/mid 80s. Lows will cool into the mid/upper 60s. Similar conditions are forecast on Thursday. A cold front located to our north, will approach the forecast area later in the day. Depending upon timing, it could bring higher rain chances as well as stronger storms.

The Weather Prediction Center has most, if not all of the area in a Marginal Risk for excessive rainfall this week. Thus depending upon when and where rainfall occurs, if it is heavy and falls on an area that is very wet to saturated from recent rains, runoff will occur and bring risks of flash flooding and flooding across the Tennessee Valley through Thursday. Thunderstorm chances will remain in the forecast as well, except "general" intensity convection is anticipated with the usual gusty outflow winds and heavy downpours. Storms in high PW regimes can become electrically active as well.

LONG TERM

(Thursday night through Monday) Issued at 1120 PM CDT Mon May 25 2026

Most guidance shows the surface front pushing south of the area by Thursday evening. Cloud cover should linger though behind the front over the area. Not much appreciable cold air advection or drier air shown right behind the front. This combination should keep overnight lows on the warm side in the lower to mid 60s. This should also provide a brief break from rainfall activity.

Most guidance moves the front northward around daybreak on Friday into northwestern Alabama and possibly some of our southeastern counties in AL. Forcing is not very strong, but does move back over the area. Instability between 1000 and 1600 J/KG (some guidance a bit more) does develop by the afternoon hours. Shear though is very weak (~10 to 15 knots). PWATS remain high between 1.6 to 1.8 inches. So a very saturated atmospheric column will not take much forcing to produce heavy rainfall rates. A continue threat for a period of rain and thunderstorms developing during the afternoon and early evening is expected. A flooding risk will likely extend into Friday.

Much deeper and stronger forcing seems to develop in many models Saturday overnight as the main upper level trough axis moves east aloft. This could produce a concentration of heavier rainfall and some storms more so over Georgia and maybe extending west into NE Alabama. A risk for some flash flooding will likely continue on Friday afternoon into Friday night.

Models diverge on how amplified the upper level trough axis is Friday night into Saturday and into the weekend, which will have a big impact on whether the front shifts south of the area or not.

Model converge a bit more on stronger forcing and shear developing over the area on Monday. Shear is better with this system and instability is not bad. There may be some strong to severe thunderstorm threat with that system, but this is too far out in the extended to have much confidence with it.

AVIATION

(12Z TAFS) Issued at 642 AM CDT Tue May 26 2026

Showers and a few thunderstorms are expected again today with the greatest coverage during the afternoon hours. Terminals will generally be have CIGS in MVFR, however heavy rainfall can cause brief IFR CIGS and trends are suggesting CIGS could fall to IFR towards the end of the TAF period. Did not have the confidence to lower them that far yet for this TAF issuance.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Flood Watch through this evening for ALZ006>010-016.

TN...None.