A persistent dome of high pressure over the Southwest is driving the late-August heat wave across Southern California, with models showing strong subsidence and clear skies favoring temperatures several degrees above the 85°F normal for downtown Los Angeles on August 26. Coastal marine-layer effects and afternoon sea breezes introduce the main uncertainty, as variable onshore flow can cap afternoon highs in the mid-80s at official stations despite hotter inland guidance. Recent model runs reflect this tension, keeping 84–85°F and 86–87°F outcomes nearly even in trader sentiment while assigning lower probability to 88°F-plus readings that would require minimal marine influence.