Only had two of those to my memory here in NY.
And both times when they gave the Warning it was laready too late.
They never even gave an advisory first, just, "Oh, by teh way, there's a tornado here folks. Move along, nothing to see ho hum. It's only ripping teh snot out of stuff over by the schools, but your kids are okay."
That was the first one. (F1, not worth talking about really)
Tornadoes aren't very common here.
So when the second warning happened in 99, I was up at Fort Drum during AT and got to hear about how not one but 5 funnels were seen in my 'home' area.
Recently heard that one of them may have been F3, maybe F4.
*shrugs*
Thought it odd.