Photograph by Chicago Cubs (@Cubs) on Twitter
The Chicago skies were putting on quite the show on the night of June 22, 2015 when the Cubs were hosting the Los Angeles Dodgers for a baseball game at Wrigley Field.
Mammatus, also known as mammatocumulus (meaning “mammary cloud”), is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a cloud. The name mammatus is derived from the Latin mamma (meaning “udder” or “breast”). The ominous-looking clouds actually signal severe weather in the distance, rather than overhead. [source]