CEDAR RAPIDS, Iowa (KCRG) - Most of our rain so far in 2019 has come from either big lines or big complexes of rain and storms. Airmass thunderstorms are typically called “pop-up” thunderstorms and develop from daytime heating. In short, the atmosphere becomes unstable and small storm cells pop up, usually in the late afternoon. They often dissipate in the evening because, as the sun goes down, the heat goes away, too. Airmass storms rarely turn severe but can cause localized downpours.
The challenge of these is predicting where they’ll develop. It’s like a popcorn popper with the lid off: you can get an idea of when the kernels in general will pop, but not which individual kernel will pop until it’s just about to do so.