Overview

• A Four Corners high pressure system has built a heat dome over the Southwest that is shifting warmth into the Bay Area for its first significant heat event of the summer.
• National Weather Service forecasts give interior Bay Area communities a 70% chance of 90–100°F highs by Sunday.
• Coastal and bay regions will remain 20–30°F cooler than inland zones thanks to sustained onshore flow and a thickening marine layer.
• A second, more intense heat surge is expected Friday through Sunday following the dome’s merger with a Northeast Pacific ridge, pushing interior temperatures toward triple digits.
• The U.S. Drought Monitor reports the region is not in drought; rising temperatures are heightening fire risk concerns.