Thursday, March 21st Brief Overview: A surge of strong NW winds and building short period seas will continue offshore through Friday and Saturday. Much lighter winds are anticipated near the Southern California and Northern Baja coasts. The surge of higher winds and seas offshore is expected to gradually relax later in the weekend and especially early to mid next week. A small to moderate long period WNW swell will also mix in with the shorter period waves this weekend before easing into next week. Modest long period S to SW swell will also impact the waters throughout the event. These should have minor impacts on the race except very close to shore..
Detailed Forecast
Friday/Saturday: A coastal eddy sets up just off the Southern California coast. This sets up light S/SE to variable winds in the morning near the coast of SoCal and Northern Baja before trending W 5-15kts during the afternoon. Stronger NW winds are expected west of 119W, with speeds of 15-25kts likely there.
Seas close to shore and inside of the Channel Islands will be a mix of short period WNW swell 3-4 ft. at 10 seconds (except to 5ft north of Santa Catalina and exposed waters in the Outer Santa Barbara passage), long period SSW swells of 2-3ft, and similar sized long period WNW swell that moves in by Friday night and Saturday. Periods of these swells will range from 15-21s. Much larger WNW/NW wind waves are expected south of San Clemente Island and west of the Channel Islands in general, where widespread 7-11’ seas at 9-11s will be dominant. Mariners should thus prepare for rougher seas as they approach international waters.
Sunday/Monday: Light and variable winds continue close to shore in the mornings before trending onshore (west) 5-15kts during the afternoon. Winds beyond 20nm will generally be NW 8-16kts for much of the race area, except to 20kts north of 30N.
Lingering WNW/NW wind waves of 5-7ft at 10-11s will continue for much of the waters off Baja, except locally higher west of 117W on Sunday. This will continue to mix with longer period 2-4’ swells from SSW and WNW directions.
Tuesday/Wednesday: Winds very close to shore continue to be diurnally influenced with light/variable winds early trending locally onshore 6-13kts in the afternoon. Winds will be NW to N 6-13kts further offshore.
Combined seas will subside to 3 to 5 ft. on Tuesday and to 2 to 4 ft. on Wednesday. However, computer models do suggest a pocket of locally higher NW/N winds and associated wind waves just north of Cedros Island, but lower winds/seas to the south for the end of the race. These seas will continue to be a mix of fading WNW/NW wind waves and longer period SSW and WNW swells. Even longer period forerunners of a new NW swell are expected to mix in with this on Wednesday.
Expert Analysis. Computer models continue to agree that stronger (~1032mb) high pressure will rebuild over the Northeast Pacific Ocean through the end of the workweek. This will set up a surge of strong NW/N winds offshore of California and Baja for Thursday and Friday. Associated short period wind waves will also build and be most noticeable south of San Clemente Island.
However, there is now good agreement in the various computer models that a coastal eddy will form off of Southern California and impact the nearshore winds for the beginning of the race. Light S/SE to variable winds should be expected nearshore from this off of Southern California and Northern Baja through the beginning of the weekend.
The strong high-pressure system that is responsible for this surge of NW winds and seas offshore is forecast to weaken later in the weekend and early next week. As a result, winds and seas even offshore will begin relaxing for the end of the event.
Other Swell. A weakening storm that continues to move through the central North Pacific that will send a small WNW swell to the region over the weekend. This will gradually ease from north to south for early to mid next week. This will also mix with small S to SW swells from recent storm activity in the Southern Hemisphere. The Southern Hemisphere swell activity is expected to linger throughout most of the event. Finally, another storm is forecast to swing through the NE Pacific this weekend and early next week. The beginning of the associated long period NW swell will move into the waters off Baja late on Tuesday and peak over Wednesday and Thursday. These swell events should be mainly at or below 4ft in deep water except to 5ft for the initial WNW swell this weekend. Mariners should be advised of associated hazards very close to shore as these long period swells shoal.
Prepared by Mark Willis and Kevin Wallis
Surfline/Buoyweather/
