Definition

The term Diablo winds refers to winds that flow from the east or northeast to the west up and over the Diablo Range (part of the California Coast Ranges in the U.S.) and down into the East Bay region of the San Francisco Bay area. They are similar to the famed Santa Anna winds of southern California. Wind speeds can exceed 60 mph.

Diablo Winds

Creation

The Diablo wind is created by the combination of strong inland high pressure at the surface typically over Nevada, strongly sinking air aloft due to upper-level convergence, and lower pressure off the California coast.

The air descending from aloft as well as sinking on the leeside of the Coast Ranges compresses due to the higher pressure at lower levels as it sinks to sea level where it warms as much as 11 °C, and loses relative humidity.

Warming and drying of offshore Diablo Winds