My understanding is that California has dry summers because (very
roughly) the pacific ocean is cold at our latitude, which in turn
cools the air above the ocean and makes it more dense, thus inhibing
convection, and more generally fostering high pressure. In winter, it
rains because the air above the ocean is generally cooler than the
ocean, and thus tends to be warmed by the ocean.

My question is, is the temperature of the pacific the main factor in
California's seasons? Or to put it another way, let's say the surface
temperature of the Pacific off the California coast were raised to,
say, 90 degrees farenheit (I'm not proposing we try this...) -- would
that lead to a rainy-summer-type climate?

Hi Matthew,

I would think that the water temperature of the Pacific Ocean is one
of the main factors in California's weather. During the summer, the
cool ocean will keep the evaporation of water vapor from the ocean at
a minimum. Evaporation is directly affected by temperature, the warmer
the water temperature the more the evaporation, the cooler the water
temp, the less the evaporation. You are right about the lack of
convection in the summer (with the exception of monsoon moisture) in
California. You got the right idea in the winter as storms from a dip
in the jet stream bring colder air farther south and it will pick up
more moisture from a warmer ocean. If you warm the ocean off of
California it would lead to an increase of avaible moisture for
precipitation.

Smerby
www.accuweather.com

(Matthew F. Talbot) wrote in message . com...
My understanding is that California has dry summers because (very
roughly) the pacific ocean is cold at our latitude, which in turn
cools the air above the ocean and makes it more dense, thus inhibing
convection, and more generally fostering high pressure. In winter, it
rains because the air above the ocean is generally cooler than the
ocean, and thus tends to be warmed by the ocean.

My question is, is the temperature of the pacific the main factor in
California's seasons? Or to put it another way, let's say the surface
temperature of the Pacific off the California coast were raised to,
say, 90 degrees farenheit (I'm not proposing we try this...) -- would
that lead to a rainy-summer-type climate?