Persistent high pressure across South Central Texas has sustained a late-August heatwave, with National Weather Service forecasts and model consensus pointing to highs of 98–101°F in Houston on August 21 under partly to mostly sunny skies. A heat advisory remains in effect through the afternoon, driven by strong subsidence, light southwesterly flow, and elevated humidity that limits cooling despite a possible sea-breeze influence near the coast. Recent model runs show only modest day-to-day variability, keeping the distribution centered near 99–100°F while leaving limited room for outliers above 102°F or below 97°F. Traders have aligned with these official guidance trends and historical August climatology, where comparable ridge-dominated days rarely exceed the low 100s.