popcorn storm n. a brief, unexpected rain shower or thunderstorm. Also, collectively and more formally, popcorn convection. (source: Double-Tongued Dictionary)
Further reading
It was a dark and stormy night. So begins the long and increasingly convoluted prose of Edwards Bulwer-Lytton’s best-known novel. Today the annual Bulwer-Lytton Contest asks contestants for fanciful first sentences that are similarly...
Bonnie in Jacksonville, Florida, is in search of a term that has to do with rain adhering under the eaves. She’s sure she once heard such an expression. There’s water adhesion and surface tension, as well as the Coanda effect, but none of those...