Question:
What are the dynamics behind the night and morning low
clouds seen along the southern California
coast?
I understand that the sea breeze advects moisture inland,
but
why
this particular stratus pattern and
why an intensification around the summer solstice (our June gloom)?
How
does this local weather pattern relate to the Pacific anticyclone?
Replies:
Vicki,
Your greatest period of cloudiness is winter through early June,
mostly a result of the effects of the California current, which
begins close to the central Pacific Ocean and flows NE and then
north along the southern California coast. Cool air is advected,
mixed, and lifted just enough to produce shallow stratus and
stratocumulus
clouds along the extent of the current. The Pacific anticyclone
appears to play a minor part. These clouds back off of
the mainland in the daytime as the air over the land warms and expands
(more of less pushing air, and the clouds, offshore). At night, the
air over the land cools and the clouds can spread back over the land.
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