If it's too low early morning, this possibly is not taking place, so glucose drops too low. If this is occurring, I suggest you try taking 4000 to 8000mg/day glutamine at night. This amino acid can be used by the brain in place of glucose, but being an amino it doesn't cause a sharp drop in blood glucose levels.
Sometimes, heat lightning isn't lightning at all, but a cloud reflection of lightning from a very distant storm. In other instances, it is regular lightning which has formed far off in the distance, making a flash instead of a recognizable lightning bolt.
And of course, with lightning comes thunder. Lightning heats the surrounding air to as much as 50,000 degrees Fahrenheit, which is five times the temperature of the surface of the sun! When air is heated, it expands, and this expansion is what's causing the sound of thunder.