Following a wet spring and early summer, the recent dry, hot stretch of weather is evaporating soil moisture and allowing temperatures to soar into the triple digits.
The animation above is the weekly Keetch-Byram Drought Index (KBDI), an index used to determine forest fire potential, from June 26 to July 18. The drought index ranges from 0 to 800, where a drought index of 0 (blue color) represents wet soil, and an index of 800 (orange/red color) represents absolutely dry conditions.
The drier the soil gets, the hotter temperatures can rise.
Even though annual precipitation is running 26% above normal (24.03″ observed vs. 19.05″ normal), July has been very dry in Austin. Camp Mabry has only tallied 0.39″ in the last two and a half weeks, with 0.38″ of that coming in one day. High temperatures 92º or hotter every day since July 1.
Though the hot, dry weather has dried soil enough to allow temperatures to soar to 100º+, it has not yet dried to the point of drought conditions. Notice in the images below, only a small expansion in “abnormally dry” soil — a precursor to drought — from the U.S. Drought Monitor in the past week, and lake levels remain full.