The lamps are sucking the humidity right out of the air. Get a UTH for the hot spot, ball pythons like belly heat. It will help humidity a ton. Make sure you get a thermostat though. NEVER run a UTH without a thermostat because it can get so hot to burn your snake.
This is a great thermostat for the price.
http://www.amazon.com/Hydrofarm-MTPR...4772034&sr=8-1