Severe thunderstorms precede a shot of chill

As a strong cold front moved into a warm and rather humid air mass, strong thunderstorms fired up and crossed the Appalachians. At the high of the storm at my house near Stormstown, Pennsylvania, (named for early settler Jacob Storm), there was plenty of lightning. I had my time lapse capture setup running, but no discrete lightning bolts were picked up. However, by selecting a single frame from the movie, I could see how one flash lit up the terrain as bright as daylight:

A couple of hours earlier, the local radar looked like this:

The following map shows how much colder it is across the Great Lakes than near the cold front in Pennsylvania:

In fact, it was so cold around Chicago, intense snowfall with lightning and thunder grounded or delayed more than 1,000 flights at O'Hare. Down here at the ground, thunder snow is not too common. However, if you were flying in a cloud at 20,000 feet up in a thunderstorm, it would not be surprising to see snow. At that elevation it is generally below freezing all the time regardless of season.