I don't think that was a JDAM, one can generally see a JDAM coming down. They're pretty big and slow. I watched it a dozen times and never could see one coming down.
That secondary explosion created such a large bright fire ball above that it cast an intense band of light across the ground which quickly moved away. I think it moved away as the fire ball climbed into the sky.
I think that it was 155mm artillery, and the first shell created a hell of a secondary explosion, and that last one possibly lit off a much smaller secondary explosion. Or maybe it was just what it was blowing up in that caused that fairly large white cloud. Maybe masonry dust, that building looked like it was made of concrete and plaster.
There was one between the first and last which missed behind and to the left, which didn't do that much except look like a 155mm shell hitting in an open field.