I recall the 74 storm, here in Iowa, first time I have ever witnessed a green-grey sky, very unnerving...
Yep. Goes darker and darker, then takes on a notably green tinge.
i was outside of Detroit...and never saw sky like that, before or since. Could not believe how low the clouds were...almost tree top level. The clouds were racing in opposite directions....with an eerie type darkness the entire day. While no tornado struck my area, you could tell something really bad was happening else where...