We have high confidence that we will have strong to severe weather this evening and overnight into Tuesday. This is a particularly volatile atmospheric setup that is the most impressive we have seen since the Spring severe weather season. Also, with the timing of this event taking place primarily overnight, it makes for a more serious event.
The Storm Prediction Center (SPC) in Norman, Oklahoma has placed most of the Tennessee Valley under an “Enhanced” Risk for potential severe weather their severe weather outlook. Enhanced Risk is a scale of three out of five, five being the most hazardous.
With this particularly impressive severe weather setup, ALL modes of severe weather will be possible. Damaging wind gusts and large hail are both possible. Additionally, there is the threat for tornadoes, some may be strong and long-lived. There will also be the potential for heavy rainfall and isolated flash flooding.
The system should come through as a line of thunderstorms, but there can also be a few super-cellular storms out in front of the main line.
This is the preliminary time line for the earliest arrival of the main line of thunderstorms as of Sunday evening. This timeline is fairly broad due to the uncertainty of the exact storm arrival at this time. Overnight severe weather is dangerous and it is important to be aware of the latest forecast. This timeline will likely shift a little by Monday afternoon.
CAPE (Convective Available Potential Energy) or “thunderstorm fuel” is forecast to be relatively high, especially for the fall season.
There is also a very strong low-level jet at roughly 5,000 feet that will add to enhanced shear (turning) in the atmosphere. Both, along with atmospheric lift, are keys to strong thunderstorm development.
Please start preparing for potential severe weather as early as possible. Make sure you know where your “Safe Space” (interior room away from windows on the lowest level) is at home, work and school. Also, be sure to have multiple ways to receive weather warnings as they are issued.
The WAFF 48 First Alert Weather App is a helpful tool that will alert you to severe weather and can even stream our coverage from the app if your power goes out.