Coastal Winds

The new high resolution forecasts (4km grid spacing, initialed 4 AM) are in and the potential for a significant coastal wind event remains. Here are two plots of sea level pressure and surface wind speed for 4PM, 10 PM, and 4 AM, starting on Sunday afternoon. A deep low center moves up the coast and sustained winds on the coast are 45-50 kts. Gusts could easily be 15-20 kts higher.

Some of you have noted the tendency for coastal acceleration..and this does occur--in fact I just finished a paper on coastal windstorms where I talk about this effect. The interaction of onshore flow with the coastal terrain produces the speed up.


The Portland NWS has now put up a storm watch for the Oregon coastal waters. From their statement:

A STORM WATCH IS ISSUED WHEN THE RISK OF STORM FORCE WINDS OF
48 TO 63 KNOTS HAS SIGNIFICANTLY INCREASED...BUT THE SPECIFIC
TIMING AND/OR LOCATION IS STILL UNCERTAIN.  IT IS INTENDED TO
PROVIDE ADDITIONAL LEAD TIME FOR MARINERS WHO MAY WISH TO
CONSIDER ALTERING THEIR PLANS.

The 10 am run is just in and the story has not been changed.
Here is the sea level pressure and precip chart for Monday
morning.  One low after another rotating around. And California
is going to get hit hard with precipitation...a classic for El
Ninos.