textproduct: Huntsville

KEY MESSAGES

Updated at 1145 PM CDT Sun Apr 26 2026

- Low medium chance for severe thunderstorms later this evening into early Tuesday morning, especially in NW Alabama. Further east, this threat will linger until just before daybreak on Tuesday. - Low to medium chance of severe thunderstorms Tuesday evening into Tuesday night.

- Rainfall totals of 1.5 to 2.5 inches are forecast through Wednesday. Another solid half of an inch to an inch will be possible Tuesday night into Wednesday morning.

NEAR TERM

(Tonight) Issued at 133 PM CDT Mon Apr 27 2026

The outflow boundary that was moving southeast from NW Mississippi just before noon, has pushed into central/northeast Mississippi at this hour. Some showers are developing on radar at this time in central Mississippi along that outflow boundary stretching along the AL/MS border. A strong cap is still in placed based on the depth of the 50 dBZ cores and lightning is beginning to develop with some of those cells.

A very unstable airmass is in place west of the frontal boundary with SBCAPE values estimated via SPC meso-analysis over 3000 J/KG. Eastward across the TN/AL border SBCAPE is still between 1000 and 2500 J/KG, despite lower dewpoints. More than enough effective shear is in place for severe thunderstorm development if the EML can be broken through to allow robust convection. 2-6km lapse rates are around 8.0 degrees/km. Luckily, low level helicity remains very weak.

Earlier some models hinted at the EML(cap) breaking earlier in in the evening. This seems to be bearing out (maybe even a tad earlier) based on this latest radar development in Mississippi. We will have to watch the storms as they move NNE towards NW Alabama over the next few hours. These would approach the AL/MS border between 2:30 PM and 3:30 PM if they hold together. At this time, helicity looks too weak for tornadic development with these storms, but large hail and damaging winds could occur if they can break the cap as they move into NW AL.

We still expected the interaction of the outflow boundary as it moves further east and the front to be the main impetus for any isolated to scattered convection that develops during the late afternoon afternoon into the evening hours. This may produce a few discrete supercells slightly earlier than originally thought (earlier thinking was 8 PM to 11 PM) based on radar trends. However, a strong EML is in place, so that might delay robust convection until the early evening hours in NW AL.

NW Alabama continues to be in a slight risk of severe thunderstorms. This looks to be the area most at risk for some large hail, damaging winds, or a tornado or two.

Further east, surface based instability should drop off more quickly this evening after 10 PM. Though enough elevated instability and dry air aloft could linger through 6 AM for a severe thunderstorm producing marginally severe hail or damaging winds. Strong forcing pushes into the area around midnight ahead of a pre-frontal trough axis. If any discrete cells earlier in the evening can hold together, then a very low tornado threat may continue until around 10 PM near the I-65 corridor. A good 3/4 to 1 inch of rainfall seem reasonable or most areas through daybreak on Tuesday.

SHORT TERM

(Tuesday through Thursday) Issued at 1145 AM CDT Mon Apr 27 2026

The atmosphere should be pretty worked over by the early morning hours as the pre-frontal trough axis pushes southeast into southern Alabama. Subsidence and a redeveloping strong EML should limit precipitation chances. Most guidance shows a strong EML redeveloping during the morning hours into the early afternoon hours. This should keep convection at bay until later in that evening, as a surface low forms along the front over Arkansas or Missouri. Most guidance shows this occurring over Arkansas and moving northeast along the primary cold front lagging behind the pre-frontal trough axis that had already moved through the area. This should setup a very sheared and dynamic atmosphere ahead of it. Lapse rates climb to between 7.5 and 8 degrees and shear and helicity are very strong. Instability is high enough for robust updrafts as well. Luckily the EML should help to keep a lid on things until stronger forcing pushes into the area Tuesday evening in NW Alabama and proceed east into the early morning hours (~4 AM) before moving southeast of the area. GFS looks to be having convective feedback issues, since coupling jet structure dynamics don't seem to be very evident. However, with PWATS increasing to between 1.5 and 2.0 inches in that timeframe, we will have to watch for training/flash flooding issues.

It does look like we get a break from the rainfall and storms during the day on Wednesday. Models keep a very low chance (20-30 percent in the forecast Wednesday afternoon. This may be overdone and we may not see any rainfall in the afternoon. Some mostly cloudy conditions could linger in the early afternoon hours. Some cold air advection will start to push into the area behind the cold front late in the day. Highs between cloud cover and some weak cold air advection will likely limit highs to the 75 to 80 degree range.

Significantly colder and drier air pushes into the area Wednesday night into Thursday. Lows should drop back into the upper 40s to lower 50s Wednesday night. As the cold front edges north into central Alabama on Thursday afternoon, mostly cloudy conditions will return. Highs will be noticeably cooler only reaching the upper 60 to lower 70s.

LONG TERM

(Thursday night through Monday) Issued at 1145 AM CDT Mon Apr 27 2026

Cloud cover should increase Thursday night, but still likely be on the cooler side of the boundary. Lows will likely stay on the lower side one more night dropping back into the upper 40s to lower 50s again.

Models diverge significantly as we move towards the weekend concerning how quickly and where a surface low moves and interacts with the front near the area. This evolution will have a very big impact on our weather over the Tennessee Valley area. Some models develop the surface low over Louisiana/Mississippi and other models well south in the Gulf of America. The northern solution would produce widespread heavy rainfall and some possible severe weather over the southeast (including northern Alabama and southern middle Tennessee). While the other solution would keep all the rain and storms south of the area and concentrated more over the southern Alabama/Georgia into the Gulf of America.

AVIATION

(18Z TAFS) Issued at 1232 PM CDT Mon Apr 27 2026

VFR conditions will be predominant through 6Z or 7Z at both terminals. However, there is a low chance period (PROB30) of TSRA at KMSL between 01Z and 05Z and at KHSV between 03Z and 07Z. Then expect predominant MVFR to IFR VSBYS with -TSRA. This may need to be amended for stronger storms and lower CIGS/VSBYS as convection develops. After 12Z expect mainly -SHRA with CIGS below 2000 feet.

HUN WATCHES/WARNINGS/ADVISORIES

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