Dennis’ Local Almanac

By DENNIS McTIGHE

Laguna latitude 

Here on Sunday, the 19th, the sunrise occurred at 6:57 a.m., and our sunset this evening will be at 7:03 p.m. The Vernal Equinox is today, an event in which the entire globe is supposed to see exactly 12 hours of sun – which includes both the Northern and Southern Hemispheres. 

However, here at our latitude, the exact 12 hours happens a few days before the 21st, more like the 16th or 17th. The same goes for the fall when the actual 12 hours happen around September 24th or 25th instead of the 21st. 

At any rate, the beginning of spring has arrived in our hemisphere while the beginning of fall is officially underway in the Southern Hemisphere. It’s all about how much the Earth is tilted toward the Sun. The Equator sees an equal amount of sun the whole year at around 12 hours.

Over the course of the next several days, our first significant long period Southern Hemisphere groundswell is expected to make an appearance at our local south facing beaches with sets approaching 8-10 feet – at some spots. These swells are traveling a long distance, upwards of 6,000-7,000 miles from their source to their landfall here in Southern California. It will take a week or more for them to travel those thousands of miles to reach our beaches. 

The strong systems that produce these big swells are born in a region known as “The Roaring 40s,” where most of these lows form in a belt from 40-50 degrees south latitude from the Equator, hence the moniker. It is much like our hemisphere’s storm belt, in which most storms are born in that area. It is roughly at 40-50 degrees north latitude where these storms begin their long journey to the east or ENE across the Pacific, eventually winding up at their landfall on North America’s Pacific West Coast (somewhere between the Mexifornia border all the way up to Southern Alaska’s west coast). 

Southern Hemisphere storms travel to the east or ENE as well but do not encounter major landforms as they push on. They pass under South America’s southern tip known as Tierra del Fuego and continue their journey into the Atlantic passing to the south of Africa’s Cape Town and eventually, on occasion, going full circle.

Not every storm down there produces large swells that make it all the way up here. Don’t get me wrong, as all storms down there do push swells of varying strength ahead of these systems, but it’s all about the direction in which these lows are moving. Storms that are moving straight to the east won’t push swells our way as a rule, affecting the beaches well to our south like in Mainland Mexico, Central America and much of the west coast of South America. 

It can be totally flat here in Southern California, but in a place like Puerto Escondido, the waves can be 20 feet far to our south way down there in Southernmost Mexico and points beyond. However, if that storm is pushing to the ENE, that opens up a much wider swell window – and that’s when it gets huge up here as well. 

One such storm in July 1996 was so strong when it was about 600 miles south of Tahiti, giant waves were recorded from Tahiti all the way north to the coast of Alaska. That very swell produced sets up to 15 feet here in Laguna on July 24, 1996, with sets as big as 25 feet at Newport’s Wedge. 

Here comes swell number one here in 2023 – on Sunday at 12 p.m., waves are beginning to arrive from the south, so stay tuned!

See you next Tuesday!