What is This?

These photos were taken in the eastern sky between 7:05 and 7:15 this morning. When we first saw it, the sun was just beginning to peek over the horizon. There was a very bright light that appeared to be moving up surrounded by an umbra of light. Just minutes later the ball was gone and only the "tail" remained. As soon as the sun lit up the sky enough, the whole thing was obliterated.

The top photo was taken last. The bottom photo is the same as the middle one but I used the "auto contrast" feature in Picasa2 and then cropped it. This was much more spectacular in person than the camera was able to capture.

So, any ideas on what it is? Our guesses range from atmospheric gases lit up by the sun to an exploding meth lab.

Update: Thank you, Polly. This is apparently what we saw.
Update II: And here's a link from our local newspaper.