Air Mass
Thunderstorm
Generally, a thunderstorm not associated with a front or other
type of synoptic-scale forcing mechanism. Air mass thunderstorms
typically are associated with warm, humid air in the summer months;
they develop during the afternoon in response to insolation, and
dissipate rather quickly after sunset. They generally are less
likely to be severe than other types of thunderstorms, but they
still are capable of producing downbursts, brief heavy rain, and
(in extreme cases) hail over 3/4 inch in diameter. Since all
thunderstorms are associated with some type of forcing mechanism,
synoptic-scale or otherwise, the existence of true air-mass
thunderstorms is debatable.