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Fog (Marine Layer)

Notes:

The temperature difference between the land and sea forms the basis for the most familiar weather pattern in the Bay Area – the almost daily intrusion of the Marine Layer (or as it is more commonly known Fog).

Air being circulated by the High is warmer and Moister then the surface waters near CA. When these winds meet the cold coastal water they form Stratus clouds (or high fog). This fog bank is relatively persistent during spring and summer.

Inland the cycle starts in the morning. At sunrise the the previous nights fog is starting to burn off. Close to the water the thick stratus layer prevents the early morning sun from reaching the ground moderating its temperature. As the sun gets higher the inland areas heat up. The hot air rises forming a low pressure area relative to the ocean.

A cool moist wind develops as the higher pressure air over the ocean flows in to equalize the pressure of the inland low. Since this is a purely local event the winds are not affected by the earth’s rotation.

The onshore breeze brings this stratus layer with it as the land cools. This can occur in the afternoon in places like San Francisco and Salinas, but usually requires radiation cooling for San Jose.

The air that rose from the inland areas had to go someplace. It travels out over the ocean to maintain the ocean high pressure system. This forms a temperature inversion that is familiar to those that use Montebello.

Note that 1996 Scripps study (in references) changes some aspects of this model. This is something I am going to research further.