The Storm Prediction Center updated the severe weather outlook Monday morning to reflect the ‘greatest’ severe weather threat remaining south of the Tennessee Valley; it does not clear us of any risk at all, though. The dark green area (marginal) represents the lower risk area; the yellow and orange represent a bigger threat from severe storms.
The difference between no real threat and a chance of active storms for the Tennessee Valley hinges on how unstable the atmosphere can get this afternoon and evening.
A large mass of rain and embedded non-severe storms in Mississippi and southern Alabama should limit the instability over North Alabama and Southern Tennessee through the evening; however, any clearing for more than 30 to 60 minutes could quickly change the situation.
What to expect Monday and Monday night:
- Rain is likely; expect about 0.25″ to 0.75″ across the Tennessee Valley with a few spots getting much more than that (upwards of 1-2″ in some communities in Cullman, Blount, Etowah, Cherokee and DeKalb Counties).
- A clearing of rain and cloud cover over northwestern Alabama may help to destabilize the region between Marion County in Alabama northeast into Hamilton County in Tennessee. Destabilized air has a greater tendency to rise, allowing the formation of strong to severe storms. The greater risk of ‘severe’ weather will be south of the Tennessee Valley area, but we still need to be alert for any quick changes that could allow storms to maintain strength farther north.
- It will be windy today – especially on the ridge tops. Occasional gusts above 25-30 mph are possible.
- The threat of rain and storms ends between 11 PM and 1 AM.
Swipe through the images here for some visualization of how we expect the day to play out:
Stick with us through tonight; we’ll keep you posted!