Wayne Blicha has been harvesting giant kelp (Macrocystis) on the Central Coast for more than 10 years for the Abalone Farm Inc. in Cayucos. He has never seen such a heavy surface canopy of this marine algae before. Giant kelp can grow at the unbelievable rate of 1 to 2 feet per day!
“Usually the peak growing season for giant kelp occurs in April through May during the height of the upwelling season, but this year, the peak growing season seems to be extended into August,” he said.
Jim Kelly, a marine biologist at Pacific Gas and Electric Co.’s Diablo Canyon nuclear power plant, said that this year has been well above average for kelp and other marine algae growth.
“Bull kelp (Nereocystis) is a large kelp species that is closely related to giant kelp and has also been flourishing along our coast,” adds Scott Kimura, a marine biologist with Tenera Environmental, a local consulting firm.
The meteorological towers at Diablo Canyon have recorded some of the most persistent northwesterly winds during the month of August in decades, producing an unusually great amount of upwelling for that time of the year.
As the northwesterly winds blow parallel to our coastline, the friction of the wind causes the ocean surface water to move. The Coriolis force turns the surface water to the right, or offshore, causing upwelling along the coast as cold and nutrient-rich subsurface water rises to the surface along the immediate shoreline.
This condition, combined with a strengthening of La Niña (colder than normal ocean water in the equatorial and eastern Pacific), is producing well-below-normal water temperatures and optimum growing conditions for kelp this summer.
This August, there have been days when the average water temperature has reached only 51 degrees. Normally, it averages about 57 degrees during August, according to records kept since 1976 at the Diablo Canyon Ocean Lab.
As a teenager growing up in Sonoma County, I always looked forward to August and September to go abalone diving in anticipation of warmer seawater temperatures. This August, the wave-rider buoy off Point Reyes reported water temperatures as low as 48 degrees, the coldest in August on record since the buoy was first deployed in 1996.
These cold water temperatures, combined with a series of upper-level, low-pressure troughs over California, have produced an abnormally cool and mostly overcast summer along the coast.
At the same time, world temperature data released by the National Oceanic and Atmospheric Administration’s National Climatic Data Center confirm that 2010 has been hot. In fact, the first nine months of this year tied 1998 as the warmest on record globally.
Which leads to the question, what can coastal California expect with a warming climate? One possible scenario could be more persistent northwesterly winds and a greater amount of upwelling.
Let me explain: As the Central Valley warms, it could produce a deeper thermal trough, which is so often a predominant weather feature during the summer and fall. A deeper trough would produce a stronger pressure gradient between the waters off our coast and the interior, producing a greater frequency of occurrence of northwesterly (onshore) winds and cooler air temperatures at the lowest levels of the atmosphere.
None of this is comforting, considering the great amount of uncertainty about our climate. Whether you feel climate change is caused by human activity or just a natural cycle, becoming more energy efficient can’t hurt.
To learn more about energy sources that are free of fossil fuels, log on to the NEXT100.com website. It’s supported by PG&E and provides an in-depth look at the intersection of clean energy and the environment.
This week’s forecast
A weak and dying cold front will migrate southeastward down the coast this morning and will bring light rain as far south as Half Moon Bay and variable mid- to high-level clouds along with areas of patchy fog to the Central Coast. San Luis Obispo County will be on the dry southwest coordinate of this system and will not receive any rain.
Today’s temperatures will range from the low 60s along the northwesterly facing beaches (Los Osos, Morro Bay and Cambria) to the mid- to high 60s along the southwesterly facing beaches (Avila Beach and Cayucos). The coastal valleys (San Luis Obispo) will reach the mid- 70s, while the North County will range between mid- to high 80s.
Strong to gale force (25 and 38 mph) post-frontal northwesterly winds along the coast and clearing skies will develop Monday. Dry and breezy weather and generally below-normal temperatures look likely through Thursday.
A high pressure ridge is forecast to migrate across Southern California and finally bring warmer temperatures to the Central Coast on Friday and Saturday.
This morning’s 3- to 5-foot west-northwesterly (290-degree deepwater) swell (with a 7- to 11-second period) will continue at this height and period through this afternoon. Increasing northwesterly winds will produce a 4- to 5-foot northwesterly (320-degree deepwater) sea and swell (with a 4- to 9-second period) tonight, increasing to 5 to 7 feet on Monday and will remain at this height and period through Thursday.
At about the same time, a 3- to 4-foot west-northwesterly (285-degree deepwater) swell (with a 13- to 15-second period) will arrive along Monday night and will remain at this height but with a gradually shorter period through Thursday.
The charts and models are indicating a strong Gulf of Alaska (967-millibar) storm developing later this week. If this storm develops as advertised, it will produce a 7- to 9-foot northwesterly (290-degree deepwater) swell (with a 15- to 17-second period) Friday through Saturday.
Arriving from the Southern Hemisphere: Today’s 2- to 4-foot Southern Hemisphere (200-degree deepwater) swell (with a 14- to 16-second period) will gradually decrease through Tuesday.
A 1- to 2-foot Southern Hemisphere (225-degree deepwater) swell (with an 18- to 20-second period) is forecast next weekend. John Lindsey is a media relations representative for PG&E and a local weather expert. To subscribe to his daily weather forecast or ask a question, e-mail him at firstname.lastname@example.org.