And that's how a thunderstorm off the coast of India might trigger a pattern of events which led to the weather switch last spring.

BBC: Met Office three-month forecast was 'not helpful'

"There will be some thunderstorm activity, but the risk of severe weather has pretty much disappeared on the East Coast, " said Bruce Terry, a meteorologist with the National Weather Service in College Park, Md.

NPR: Out With A Whimper: Storms Over In East, South