Oops, being a flat-lander I didn't think of that aspect - I need to get up to the mountains for my soul's sake!
Thanks for the reminder.
You can see such a thing frequently in the Bay Area. Tourists go out to the Golden Gate to watch the wall of fog come whooshing in on sunny late summer afternoons.
It’s very striking to watch the marine layer come and go in certain locales. Just south of Half Moon Bay is another, they’re right on the verge of cool, misty northern California and warmer, sunnier points south.