LUBBOCK, Texas — It’s the first day of May, which means that we’re getting into the heart of severe weather season. The South Plains has already seen a couple of tornadoes and is likely to see more severe weather as we head into the peak of the season.
We’re kicking off May with Kellianne’s Weather Klass on how tornadoes form.
Tornadoes can be a fascinating, yet scary sight to see. They start off like any other thunderstorm and share most of the same ingredients. To recap, in order for a storm to form you need moisture, instability, and lift. But what makes a tornado different than a thunderstorm is an ingredient we call wind shear. Wind shear is the change in wind speed and wind direction as you go up in the atmosphere. Wind shear helps put the “twist” in the twister…and if you don’t have *any* wind shear, you won’t have tornado development.
The structure of the thunderstorm can get pretty complex, but here’s a simplified version. Of course you have your cumulonimbus cloud, or thunderstorm cloud, and the shelf cloud where there is precipitation falling. You usually see the shelf cloud as the thunderstorm begins to move in signifying rain is on the way. Behind that shelf cloud is typically where the tornado will form. It starts out with what we call a wall cloud, which is the base of the tornado. As the wall cloud goes into a more favorable environment, the storm produces what we call a funnel cloud. This funnel cloud is the start of the tornado where you start to see the stereotypical shape of a tornado, but it is *not* considered a tornado until it makes contact with the ground. Once it makes contact with the surface, then it is considered a tornado.