From xxxxxxxxxxxx@sbcglobal.net
“Mike said the gradient to Stockton would affect Natural Bridges and then the gradient to Bakersfield would affect Waddell. How is that? I would think either gradient would affect either one almost equally.“
Hi XXXXXXX,
Thanks for the Feedback!
As you can imagine, condensing complex wind flow patterns into mere words in a forecast is hard. So a simple statement regarding Waddell vs. Natural Bridges vs pressure gradient towards Stockton vs Bakersfield needs to be clarified.
So here is an image I made to illustrate the generalization I was trying to make in the forecast.
Looking at the image, notice the North Pacific High’s surface strong NW winds about 80 miles from shore. Those winds are weaker near shore due to land fraction.
However, for some locations, those weak winds are accelerated by the effect of pressure gradients along the coast and/or through gaps in the Coast Range. Since Waddell has cliffs behind the beach the acceleration is more like a one-sided venturi created by low-pressure towards Bakersfield and the Southern California Deserts via the Salinas Valley, the San Luis Obispo area and past Jalama. The RED arrows inland represent this effect. The pressure gradient towards the Stockton to Fresno area plays a lesser role in these winds.
Now, notice the black arrows. As the wind passes Waddell, Scotts, and Davenport it may be accelerated in the Natural Bridges IF there is a strong pressure gradient through the Pacheco Pass, over the O’Neil Forebay to the Stockton/Fresno area. Indeed on days when the NW ocean winds are weak Natural Bridges can have low-teens winds when Waddell is dead if the Stockton/Fresno pressure gradient is strong. Once again the pressure gradient to Bakersfield can help the Natural Bridges winds but to a
lesser extent than the Stockton gradient.
So if I made the forecast longer and more detailed, I would have said:
” The pressure gradient to Bakersfield helps the Waddell winds and is also aided a bit by the gradient towards Stockton/Fresno. While the Natural Bridges winds are helped by the Stockton/Fresno pressure gradient with some aid from the gradient towards Bakersfield.
But the reality is that most people would never read such a long-winded forecast if I did the same for every site in the Bay Area.
Hope this helps!
Here are some photos and videos for you: https://windnotes.smugmug.com
Mike Godsey