The Windiest Place along the West Coast

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As the U.S. West Coast enters the warm season, one area is getting very windy, particularly during  the afternoon and evenings.   Day after day this region will be hit by 20-30 mph winds, often with higher gusts.   A region, where the afternoon is often too windy to be on the beach, with wind-driven sandy stinging and making life unpleasant.  Give up?

It is the coastal zone stretching from southern Oregon into northern California, and out a hundred miles or so into the ocean.

Here is the sustained wind forecast of the UW WRF model for 5 PM this afternoon.  Notice the greenish area along the West Coast, with sustained winds of 30 kts or more?

Now examine the closer view from the 12-km domain.  Strong northerly winds stretch from just north of Brookings, Oregon (on the southern OR coast) to just north of San Francisco. You will also note a large change in sea level pressure over than area (solid lines), which has a lot to do about why we have strong winds there. 

So why the strong winds in this area during the warm season?  In the spring the East Pacific High strengthens and moves northward.   At the same time, the desert southwest of the U.S., warms and pressure falls.   So with rising pressure over the NE Pacific and falling pressure over the U.S. Southwest, an area of very strong pressure difference develops between them....over northern CA and southern Oregon.   Large pressure differences result in strong winds.

But as the infomercials always say, WAIT, THERE'S MORE!  The area of large pressure difference produces northerly winds over the coastal ocean, which in turns leads to upwelling...water coming up from below in the coastal ocean.  Those upwelling waters are COLD.  So we have very cold water offshore, and the land gets warm during the day.   The result is a large temperature gradient (peaking during the warmest time of the day), which enhances the pressure gradient even more, producing a super sea breeze.     So the morning is windy, but the afternoons are savage.

Lets take a look at the coastal winds for the past few days.  Here are the peak gusts at Buoy 46027...just offshore of the CA/OR border.  Wow...winds right now are gusting to NEARLY 45 knots (52 mph).

Or how about Cape Arago, Oregon (not far from North Bend)?  Almost 35 knots over land.  Can you imagine what that would be like on beach?   Similar winds are also found at Crescent City, CA (see below).

The northerly summer winds are so strong along the southern Oregon coast that a lot of trees are bent southward.  Want proof?  Check out this picture taken at Brookings:

I better stop before I get into trouble with the Brookings, Oregon Chamber of Commerce.  You might think this would be a good area for wind turbines, but the lack of transmission facilities and excessive strength of the winds might make it a poor choice.  But the cold water does help produce lots of coastal fog and that gives us the magnificent redwoods, which depend on fog drip for summertime water.

A reminder for those near Portland, Oregon...I will be giving a free public lecture on the Future of Weather Forecasting at the OMSI science center (more info to the right or here), at 10 AM on Saturday.

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