The NPH is still creating an eddy near San Francisco.
by Mike Godsey, mike AT iwindsurf.com
For weeks the Bay Area has seen one counter-clockwise spinning eddy and/or low-pressure system to our west. The resulting southerly coast wind has held the typical NW coast winds far from shore. The result of all the southerly flow has made for the worse Waddell, Coyote and 3rd. Ave. season in many years while greatly benefitting Pt. Isabel, Larkspur, Brickyards/Peacock Gap and often Sherman Island.
Today, Sept 4, 2018, the North Pacific High is under attack from the north by a wintry Gulf of Alaska storm as well as a couple of tropical storm west of Baja. But, as you can see in this animation, the North Pacific High still continues to create a counter-clockwise spinning eddy just west of the Bay Area.
Why? Notice how the isobars of the North Pacific High are bulging inland into far Northern California and the Pacific Northwest. This makes our ocean winds and the winds aloft turn from NW to more NNW to even NNE. And this, in turn, creates a combo of wind shear and a low pressure to our north that stirs up an eddy.
We should see a return to a more typical NW coast winds this Friday.