Welcome to San Francisco (north) with a healthy blanket of marine clouds entrenched across Puget Sound. Caused by the cooling of low-level air over the cold inland water, clouds form at the top of this marine layer where high humidity and sufficient cooling produce condensation.

Typically, the strong late-spring sun quickly erodes the clouds from below by surface heating. But today, the low stratus will be stubborn to clear. The marine layer is deep to begin with, but a subtle lift in the atmosphere will cause it to thicken even more. Mist may fall out of these persistent clouds as temperatures struggle to surpass 60 degrees on the final day of the month.

But sunnier days are ahead! Onshore flow relaxes to kick off meteorological summer tomorrow, June 1. The marine layer will be shallower, allowing the sun to erode the stratus sooner, bumping daytime temperatures into the low 70s for the rest of the week.

Meteorologist Kristin Clark
The KOMO 4-Cast Team

Updated Wednesday Afternoon{/strong}