UpperRidge2ANIM This video from this Friday May, 31 shows the clouds and winds at about 18,000 feet in the pacific west of California. The dark green areas are high levels of moisture. The dark gray areas are very dry air. Notice the northward extending loop in the upper level clouds. This is called an upper level high pressure or ridge. Far below it is the surface North Pacific High which so often drive the winds on the California coast.

I know it really seems like geek speak when the forecast says something like ” an upper level ridge targets California bringing a heat wave and strong winds to the Southern California coast and weak winds in the San Francisco bay especially inland of Treasure Island.”

How can events almost 3 miles overhead jack up the wind in Southern California and weaken winds in much of the Bay Area?

upperRidgeGraphicBelow is a simple version of the answer in words and pictures.There is also a quiz at the bottom. Take a shot at it and send your answers to mike@iwindsurf.com    Mike Godsey