Weather Underground

The Weather Underground, or Weathermen was a violent leftist group, active mostly in New York City in the 1960s. They took their name from the Bob Dylan song, "Subterranean Homesick Blues".

...you don't need a weatherman to know which way the wind blows...

Their ideology was explicitly communist and revolutionary. In one famous incident, several members were killed in the "Greenwich Village Explosion", in which amateur bomb-makers immolated themselves preparing for a terrorist attack on Fort Dix.