Persistent high pressure and mostly sunny skies over central Texas are supporting afternoon highs in the low-to-mid 100s°F for Austin on August 21, with National Weather Service guidance centering near 102–103°F and some guidance reaching 104–105°F. Strong solar heating under clear conditions, combined with light southerly winds and low-level mixing, favors the upper end of that range, while any increase in high-level moisture or slight strengthening of the ridge could cap temperatures a degree or two lower. Model ensembles show limited spread, reflecting the stable synoptic pattern, yet small differences in boundary-layer moisture or timing of peak insolation explain the tight split between the 102–103°F and 104–105°F market outcomes. Historical August maxima in Austin average near 96–100°F, so current readings sit well above climatology, underscoring why traders assign the bulk of probability to triple-digit readings.