Is You Am or Is You Ain't?

Can't resist pouring gasoline on the inferno raging here over why Iraq was cold-cocked. To wit –

Your local, highly accurate weatherman comes on the tube and makes one of the following statements:

A) Showers continue across all of the viewing area.

B) Showers are imminent across all of the viewing area.

It which case is it raining as he speaks? Discuss and show your work.

Next, what is the meaning of the word "is"?