On a day of extremes in the West (with downtown Los Angeles, for example, setting an all-time record high), Cliff Mass posted this fine example of a fog forming as a thin, low-lying layer over Puget Sound.
Sultry Pacific air was moving in from the southwest. The dewpoints in the Seattle area soared into the high 60s Fahrenheit. Mass explains:
The humidity is so large that there has been some condensation in the form of shallow fog over parts of the Sound…which is cold enough to cause this moisture to condense. Some wind was also helpful, since it mixed the water vapor towards the cold surface.