What is the weather cap? How it keeps storms from forming
It's happened many times in North Texas – a local meteorologist warns about the potential for severe weather, and it never happens. That can be blamed on something called the cap.
According to the National Weather Service, the cap is a layer of relatively warm air, usually several thousand feet above the ground, which suppresses or delays the development of thunderstorms.
Air rising into this layer becomes cooler than the surrounding air, which slows down its ability to rise further and produce thunderstorms. The cap often prevents or delays thunderstorm development even in the presence of extreme instability. However, if the cap is removed or weakened, then explosive thunderstorm development can occur.
CBS News Texas First Alert Meteorologist Brittany Rainey went to the Texas Rangers Pro Shop to explain how the cap works. What better way to explain the cap than with baseball caps, right?
The cap is an important ingredient in most severe thunderstorm episodes, as it separates warm, moist air below and cooler, drier air above, according to the NWS.
With the cap in place, air below it can continue to warm and/or moisten, increasing the amount of potential instability. Or, air above it can cool, which also increases potential instability. But without a cap, either process (warming/moistening at low levels or cooling high above) results in a faster release of available instability - often before instability levels become large enough to support severe weather development.
So the next time a severe storm does not develop, blame the cap...not the meteorologist.