Fogginess

We've had a few foggy days lately. On those days, the air is crystal clear before sunrise, with stars brilliant in the early morning sky. Once the sun peeks above the horizon, fog forms and thickens. It's ground fog that looks like pea soup as you look horizontally. But often, if you look directly up above your head, you can see blue sky and high clouds through the fog.

Our hamlet seen, or not seen, from the vineyard on a recent foggy morning.

Sometimes the fog burns off by mid-day and the sun comes out. Other times, the fog persists and the day stays gray. Those are the inversion days, when a layer of warm air forms above the ground layer of cool air, trapping the fog on the ground. The air is still, there is no wind and almost no sound, a contrast to the wind-driven fog we knew so well in San Francisco.