Set of sky flashes lit up entire sky with out any radar anomaly or storm.

Today I was up late talking on the phone when I noticed something strange.  I really don't know where else to report this. 
It looked like the whole sky took a picture, for what seemed like seconds there were two sets of flashes with a pause between the two.  The friend I was on the phone with was a former Navy so I asked him if he knew of any reports of storms or other things in the area that might have caused this.  
After 15 or 20 minutes discussing what I had seen, he had said that he checked and that there were no storms in the area at all, not even clouds.
There was no sound or bolts of lightning, nothing on the radar, just looked like someone with a really huge planet sized camera took a picture of our planet with flash.  Sorry for that description but that is the best I can describe it.  It was just the two sets and that was it. 
The flash was blueish white and looked exactly like a camera flash in a really dark room but much much quicker.