Makes forecasting very iffy
Take a look at the extended forecast for the Bay Area tomorrow. So what is going on?
As you may have noticed Bay Area wind patterns keep changing in last 10-20 years. They are very very different than the stable spring and summer pattern that prevailed for decades or longer.
At the surface there will be NW, NNW, W, WSW, SW, S and even NE winds around the Bay Area while just aloft strong NNW winds prevail.
And the reality will be far more complex than this simplified computer output. So take tomorrows forecast with more than the usual grain of salt.