(WVNS) — It’s ‘Severe Weather Awareness Week’ in West Virginia, Virginia, and the StormTracker 59 WeatherLab. The StormTracker59 team will be bringing you what you need to know to stay safe before, during, and after severe weather strikes in your town.
For the fourth day of ‘Severe Weather Awareness Week’, we’re talking about severe thunderstorms. Outside of flooding, this is one of our most common forms of severe weather in the two Virginias. Particularly during the spring season, though, they can still happen during the summer as well.
First off, it’s important to define what a severe thunderstorm is, as the definition is fairly specific:
As it’s been mentioned all week long, it’s important to know what to do when either a watch or a warning is issued. Watches mean it is time to plan and get prepared. A warning always means it’s time to act, find shelter, and have all preparations done by this point. When a Severe Thunderstorm warning is issued, it means the storm is meeting or exceeding the criteria we mentioned above.
Severe thunderstorms, like most severe weather, require fairly specific conditions to form. On the first day of ‘Severe Weather Awareness Week’, we talked about “ingredients” for severe weather. For a classic severe thunderstorm, you need at least three, sometimes four. The three you definitely need are lift, instability, and moisture. To put it another way, you need something to force everything into action and fuel to keep it going. Moisture is fairly self explanatory.
The fourth ingredient is Shear. This isn’t necessary for a severe thunderstorm, but it can often be found with them. When there is enough shear, we begin to see storms rotate and turn into what we refer to as “supercells”, the most dangerous type of severe thunderstorm. These are the storms capable of producing tornadoes. But even if they don’t produce a tornado — which many don’t — they can still produce extreme winds and are usually more efficient at creating large hail.
When severe thunderstorms strike, damage will usually follow. But the reason why damage happens is often mislabeled. When trees and power lines are knocked down, most automatically assume it was due to a tornado rolling through their area. Often times, this isn’t the case.
A majority of the damage from severe thunderstorms is caused by ‘straight line winds’, which originate from downbursts and gust fronts. These winds will cause damage all in the same direction. When a tornado occurs, damage will often end up scattered in all directions due to the rotation. Knowing the difference can help eliminate confusion and misinformation after a storm passes through.