A complex forecast is shaping up for Monday. Some of the ingredients for strong to severe storms look to come together across the Tennessee Valley, but some ingredients will be limited, meaning there’s still a bit of uncertainty in exactly how strong storms will be. The window will be through the late afternoon and evening.
The Storm Prediction Center has outlined a large part of the southern U.S. for the potential for severe weather on Monday.
Note that the highest risk (the orange “enhanced risk”) is located to our southwest. In north Alabama, we’re in the slight and marginal risk.
That means we still have the potential across the Tennessee Valley for strong straight line winds, heavy rain, small hail, and perhaps a couple of spin-up tornadoes, although the overall tornado risk looks low.
Storms will begin in the early afternoon and continue off and on through the afternoon and evening.
Lingering showers are possible overnight, but the severe threat should begin to wind down by 9-10 pm.
So, lets talk about why our risk here is a little more limited than it is further southwest. We will have plenty of wind shear for thunderstorms to tap in to on Monday.
That’s why we can’t rule out a couple of spin up tornadoes. There’s enough wind shear to support them on Monday. Despite the wind shear, as is often the case in winter, our limiting factor will likely be a lack of unstable air.
That’s CAPE (Convective Available Potential Energy). It’s essentially a measure of the amount of energy in the atmosphere a thunderstorm can use to make stronger updrafts. CAPE in north Alabama will be more limited, with higher values to our south and west, particularly in Mississippi and Louisiana. This time of year, a lot of our potential severe weather setups are high shear/low CAPE. The lack of more unstable air Monday looks to be our limiting factor. Despite this limiting factor, there may be enough CAPE to support strong winds and a few rotating updrafts that could produce brief tornadoes.
With these types of events, it’s best to be prepared, but I wouldn’t cancel your plans for the day (unless they are outdoors). Have a way to receive weather information like Live Alert 19 or a battery powered weather radio. If you get an alert a dangerous storm is headed your way, you can tune in to WHNT for more information. Know what to do if a tornado warning is issued for you, but for most of us, it will probably just be a stormy and windy Monday.
Meteorologist Alex Puckett