I lived in the Great State of Texas in the mid 70's. When I got there I was told anything West of Ft. Worth was West Texas. When I got to Ft. Worth, they said "Anything West of Ft. Worth was West Texas." I lived 25 miles from the EXACT Geographical Center of Texas. Deep in the Heart of. Where everyone was "afixin" to do things. Ah pass me a Pearl.
The only trees grew along the water courses, except Mesquite trees. While there, they recorded 1 % Humidity with warnings about driving across pastures as the catalitic converters were setting anything that had been green on fire. I don't know just how dry it has to be to be considered desert, but if while sitting in a bar of the Holiday Inn in Central Texas someone comes in and yells "It's raining!" and the bar empty's, don't be surprised when you go outside and see you wouldn't fill a shot glass with the amount of rain in the parking lot. Good luck.