Green Flash

I was beginning to watch the first game of the World Series today, I believe it was around 7:40 to 7:50 central time, when all of a sudden this green flash illuminated about 2/3's of the sky for about two seconds. It certainly was very beautiful site, kinda looked like the Northern Lights I guess. As the curious human being I am I researched about this and found out it could be “balls of lightning” or a “broken transformer.” It was overcast all day, no thunder or lightning whatsoever. I'm wondering if anyone knows what this phenomenon is, and if anyone in the Chicagoland area saw it too?



[edit on 28-10-2009 by The_Glen]

Well, it could have been anything

Its hard to tell what it is without seeing it. The well known green flash phenomenen is actually a green light at the top of a setting sun, but judging by what you said, this isn the case.

I doubt it was some meteorological phenomena if it was overcast