California’s mild winter is not going to depart without giving the Bay Area something to remember, as the National Weather Service [NWS] predicts a week of rain, powerful winds, and hazardous conditions for watercraft ahead.
NWS (a division of NOAA) warns of two large storms approaching the west coast of North America. Although areas north of San Francisco all the way up to Canada will get the brunt of the blow, the tail end of the nearest storm is still expected to soak the Bay Area, with one to two inches of rain on the “immediate San Francisco Bay shoreline and Monterey Bay” as well as between three and five inches in the “coastal mountains” regions.
The forecast anticipates rain increasingly likely in San Francisco over the course of Monday night, with a drenching continuing through Tuesday morning.
Wet weather will probably kick up again later on Tuesday and on Wednesday—NWS puts the odds of showers at around 40 percent—and then likely return in force on Thursday. A “chance of showers” will persist through Sunday.
Meanwhile, with the wet weather comes 15 to 30 mile per hour winds during the course of the week, with Monday and early Tuesday being a particularly blustery time. NWS has issued a small craft advisory through 4 a.m. on Tuesday:
“Wind speeds of 21 to 33 knots [24 to 37 miles per hour] and/or steep waves are expected to produce hazardous wave conditions to small craft. Inexperienced mariners, especially those operating smaller vessels, should avoid navigating in these conditions.”
The forecast anticipates waves of between six and eight feet from Point Reyes down to Pigeon Point near Pescadero. As the sailing site Ocean Navigator warns boaters, a NOAA warning about eight foot waves actually means that even larger surges are likely:
The wave height given is the significant wave height, which is the average of the highest one-third of the waves that may be encountered. It is not the average of all waves, nor will all waves be in this range. Some waves will be smaller and some waves will be higher. In fact, you can expect to see a wave almost twice as high.
Ocean Navigator writer Steve Tredup notes that such a freak wave—14 to 16 feet in the case of a night like tonight—is unusual even during the course of a violent storm.
But it does happen and should be factored into the risks of taking a craft onto the open water during a storm...which of course nobody should be doing anyway.
- San Francisco Bay Area Forecast [NWS]
- Small Craft Advisory [NWS]
- Waves & Your Boat [Ocean Navigator]