Most of us associate Southern California with Hollywood, beaches, and sunny weather. However, with relatively cold waters offshore and typically higher pressures over the Pacific Ocean, there is essentially a competition between air rising from the surface and sinking air further up in the atmosphere. The rising air and sinking air meet in the lower atmosphere to form a marine layer—typically low-altitude stratus clouds.
This marine layer often manifests as a thick, rolling fog at Vandenberg Air Force Base, a two- to three-hour drive northwest along the Pacific coast from Los Angeles. This means rocket launches from Vandenberg often end in disappointment for expectant viewers. This occurred most recently with the Atlas V rocket launch of NASA’s Mars InSight lander a few weeks ago, which people could hear, but not see.