Marine Layer and Fog Season Begins in Coastal California (Credit: Meteorologist Jessica Olsen)

Image Courtesy: Naval Research Lab

DISCUSSION: As temperatures warm and much of the country is thoroughly into its spring weather, California’s Central Coast is wrapping up its wet winter weather which brought unprecedented rains to much of the state, diminishing all D3-D4 drought indices for the state. While the state transitions to warmer surface temperatures as summer approaches, a common weather phenomena can be seen along the coast, fog. This fog and its water vapor rich friend the marine layer can impact traffic, air travel and ultimately overall visibility in coastal locations and some inland locations where valleys are prevalent.
 
The National Weather Service states, “the marine layer represents a difference between a cool, moist air mass and a warmer air mass.” The marine layer in a sense is similar to a sea breeze in that a sea breeze is a local wind that blows from sea to land, which is often caused by the difference in temperature when the sea surface is cooler than the nearby land mass. The marine layer in the coastal areas of California often affects visibility, as its suspension of water droplets, and salt form the critical condensation nuclei needed for this fog formation.
 
The San Francisco Bay area including the California coastline is quite susceptible to this phenomenon. We should expect to see more of the marine layer and fog to roll in on a consistent basis as forecasts call for cool sea surface temperatures coming on contact with cooler dense air which creates the inversion for a layer of these stratus clouds to form or fog if the cloud layer does not lift enough.

Below is current video of satellite footage for 1900Z of the Monterey Bay Area, notice the lack of inland breach of the marine layer into the Monterey area!
 
For information on this and other weather phenomena visit the Global Weather and Climate Center!
 
~Meteorologist Jessica Olsen
 

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References:
Service, National Weather. "The Marine Layer." NWS JetStream - The Marine Layer. N.p., n.d. Web. 10 May 2017.

Video: Naval Research Lab, Monterey Bay May 10th, 2017