Often occurring during the spring and summer time, severe thunderstorms can pack a lot of lightning, damaging winds, large hail, and potentially drop a tornado. What starts out as a normal thunderstorm can become severe and dangerous under the right atmospheric conditions.
Thunderstorms need three ingredients to form: moisture, lift, and instability. However, in order for a thunderstorm to become severe, you need a lot of instability. We measure this instability by something called convective available potential energy, also known as CAPE. The larger the CAPE you have, the more likely we can expect severe storms to form. This may sound pretty simple, but in fact there’s more to it. While CAPE is a very important parameter in order for these strong/severe thunderstorms to form, it also depends on a multitude of other atmospheric variables like CIN and shear.
Putting the jargon aside, the difference between a non-severe thunderstorm and a severe thunderstorm lies in the impacts of the storm. According to Emma Weston, meteorologist at the National Weather Service in Lubbock, there is a certain set of criteria a storm must have in order for it to be a severe thunderstorm. “Those criteria are winds that are 58 miles per hour or greater, or has hail one inch in diameter or greater. That’s about the size of a quarter. So once it reaches one of those criteria, it’s a severe thunderstorm warning.“
A severe thunderstorm can pack a lot of lightning with it, but that is not what makes a thunderstorm severe. However, if you are outside and begin to hear thunder, be sure to head inside immediately.
“So you want to stay aware of the weather. Especially in the spring and summer. We have a lot of our severe thunderstorms during that time of year. So stay aware of the weather. Make sure if you’re outside at baseball or soccer you have a plan to get back to your car for safety, for shelter. Lightning can be dangerous if you’re outside and you want to make sure you’re inside. Even though there may not be a tornado, the winds can be 60, 70 miles per hour which can be dangerous if you’re outside.”
Not only can winds get high, but these storms can pack large hail as well. When you get inside you’ll want to make sure you stay away from any windows as large hail can break them. If you’re driving when hail strikes, do not do what you think you should do and park under an overpass.
For more information on severe thunderstorms head here: https://www.spc.noaa.gov/sfctest/help/sfcoa.html