That’s easy it’s precipitation that evaporates before reaching the ground. The local weathermen only mention it a thousand times over the winter when the air is just too dry to support snow reaching the ground Hotwater
I had my geography exam yesterday. One of the questions was draw a diagram to show a type of rainfall that could've contributed to a flash flood. Course, I didn't know the answer. I ended up drawing a three part flow diagram. The temp is high so water quickly evaporates. Because the air is warm it will hold more water vapour [evotranspiration.sp.] This means when it finally gets heavy enough to rain there is a lot more in the same kind of timespan. I'm sure I got a few marks for my pretty drawings.