You are currently browsing the category archive for the ‘Meteorology’ category.
Foggy at the coast. Sunny and warm 2 miles inland.
In celebration of the return of our beloved fog to the California coast after two weeks of weather extremes: 30 mph wind gusts for a week, followed by wiltingly-hot temperatures, let’s resurrect two old books for their descriptions of California’s sea fog, also known as “Advection Fog.” Advection fog forms when warm, moist sea air blows onshore, and is brought up short from its travels where the upwelling colder water runs along the coast. When the interior warms, a wind develops and blows the fog back to sea. This is why fog brings breezes whether it’s coming or going. Some people call advection fog, “Tule Fog,” but that is a particular type of inland valley fog; completely different in both its location and how it arises. (I think people like saying the word “tule” more than they like saying “advection,” so that is why the error persists.)
The first golden oldie resource is a little volume of essays published in 1915, Nature & Science on the Pacific Coast : a guide-book for scientific travelers in the West. In the essay, “Weather Conditions on the Pacific Coast” is a single entry describing, “one of the most climatic features of San Francisco is the prevalence of fog.”
The prevailing weather condition of the City could have seven different descriptions by the locals, as it is said the Eskimos have a variety of words for snow, and indeed, sometimes the fog crawls in like cat feet, but there is another fog that pushes first a wind, then blows dramatically into the City, swirling grey gusts around the hilltops and cable cars, making the town come alive.
