Early on Saturday morning (between 2 and 3am local time) I was out watching the lightning from nearby storms. There was a storm a few miles south of my location here in San Angelo, TX, and it was getting pretty breezy in my area (presumably due to outflow). What caught my attention was the wind suddenly became extremely warm, like someone flipped a switch. I usually associate thunderstorm outflow with cool and sometimes even cold wind. What causes warm outflow?