The warm front that moved north of us last night, bringing some rain, has brought humid air back into central Alabama. With a little sun, temperatures have climbed into the 70s, and dewpoints are in the 60s, producing CAPE values near 1000 J/kg. With the front still close by, we also have some wind shear, with helicity around 200 m2/s2.
Several supercells have developed over northwest Alabama and northeast Mississippi. They are small, given the lack of deep instability, but several have hook echoes and Doppler velocity signatures that indicate rotation. One the Fox 6 cams in Hamilton showed a wall cloud in the past hour.
Severe thunderstorm warnings are in effect for parts of Marion, Winston, and Lamar counties. As the afternoon goes on, these storms will likely move farther southeast, affecting Walker, Pickens, Tuscaloosa, and Cullman counties. Given the wind shear in place, these storms may produce some wind damage and hail, and I think a weak tornado or two is possible. I am not sure why there is no severe thunderstorm or tornado watch.
Please be weather aware this afternoon in areas like Hamilton, Jasper, Cullman, Tuscaloosa, and even Birmingham.
Dr. Tim Coleman