West Coast Wind Blog: Clouds weaken local thermal wind

by Mike Godsey, mike@iwindsurf.com

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Sometimes I just have to put weasel words in the forecast even when almoat everything looks promising in the early morning. In today’s forecast, Thursday, February 21, 2019, those weasel words were “If heavy clouds to the west do not come over us the local thermal winds reach the mid to mild upper-teens strongest at Rasta and weaker for La Ventana and weaker yet for Los Barriles”

I had to put those weasel words into the forecast since there is a vague cold front sweeping down Baja from a storm system moving in to Southern California and Baja Norte. And at dawn there were hints of some of those cloud not too far away from Baja’s East Cape. And if they arrived early it would kill the wind.

By 9:30AM it was clear to me that some of those clouds were getting too close so I issued this to the forecast: “UPDATE at 9:30 AM. The most recent satellite imagery is showing some heavy convective clouds about 100 miles to the west of La Ventana and their trajectory could bring them over our mountains and perhaps over the Los Planes valley which would really weaken the wind today.”

As you can see in my annotated satellite image for today those weasel words were justified as heavy clouds inland almost totally killed the thermal winds for Los Barriles. While frequent tiny patches of cumulus clouds from the west evaporated over the western Los Planes Valley much of the morning while a swath of heavier clouds closer to La Ventana was the final nail in the coffin for getting winds above the weak low teens.