COASTAL
Marine Layer Fog
Saturated marine air piles into a low fog deck under a light onshore breeze.
How it works
A saturated coastal airmass settles into a low fog deck that drapes the headlands and isolates sea stacks above it. Unlike radiation fog it rides in on a light breeze rather than a dead-calm night, and it is a low cloud deck rather than a clear sky. Best right around sunrise before the sun burns it off. Whether it sits at your elevation and the breeze is truly onshore is the part a point forecast cannot see.
What to check in the field
This is a Watch look: the ingredients are forecastable, but whether the deck sits at your elevation and the breeze is truly onshore. A point forecast sees the moist low deck but not the inversion height, the burn-off timing, or the wind geometry to your viewpoint. Shotcast flags it so you know to go and look.
See when it's likely near you
Shotcast scores every hour of your forecast for marine layer fog across your saved locations, so you know when it's worth heading out.