Sunday, 20 May 2007

A cloud tsunami

These shots that Will took one February afternoon, as a marine layer rolled in from the ocean, help explain what the 'May Grey' is. On this occasion, we'd had a crisp, bright and sunny winter day. Then this layer blew in, stayed all night and started to dissipate by the middle of the next day.
The pic above, and the one below, were taken just a few minutes apart, looking south, down into Carmel Valley, as the layer moved in from the ocean, a few kilometres to the west (right of the pic).

We live on top of the hill Will is standing on, but a safe distance away from all these powerlines! This next pic is looking directly west:

It's very dramatic watching this cool, moist tidal wave of cloud take over the landscape. And because it's so big, it's quite awe-inspiring.

:: At the moment, we've had May Grey for four or five days - miserable! - and next month it's known as 'June Gloom'. But in the height of summer, a marine layer will last only until about 11am when the heat of the sun dries it up. It helps prevent an early build-up of heat, but it can also cause humidity at times.
So San Diego has these two big climate modifying phenomena: the occurrence of the marine layer that keeps things cool and moist in spring and summer, and the hot Santa Ana winds that warm everything up in autumn and winter. Neat-oh! No wonder everyone wants to live here, where the average daily temp is a very comfortable 21 degrees C (70F).

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