Check your facts this is NOT the blast. It is from another explosion. Has been retracted all over the internet.
Here are some facts about the weather during and after the blast. The Waco region was in a warm, humid but otherwise dry air mass at the time of the blast, with south to southeast winds at about 25-35 mph. There may have been a higher than average buildup of static electricity near the surface as the air mass was stable and ahead of an active front. At that time, the front was at least 150 miles to the northwest of the site of the blast. Now (0230 CDT) the front is about a hundred miles away and will arrive about 0700h, causing the wind to change rapidly to NNW 25-40 mph. There could be a brief thunderstorm or rain shower with the front.
Just wanted to add this to the discussion because in the usual fog of internet info-overload there are bound to be false conclusions about lightning as a cause. While I think static electricity is a possible factor, there was no active weather anywhere near the scene at the time of the explosion.
Sorry...got it from twitter feed at the Houston Chronicle..it was listed as a pic from Waco/West explosion...the time of day should’ve been my first clue!