Weather Watch

You should try experiencing real doldrums

For more than 120 days, the USS Estocin, the frigate I was stationed on in the early 1980s, was haze gray and underway, sailing back and forth between the Persian Gulf and the Arabian Sea without a port of call.

Ninety days into this arduous sea duty, the captain decided to give us a break and throw a picnic on the ship’s small steel flight deck, which we called the steel beach. We ate barbecue and everyone received one can of Budweiser beer.

At around 100 days, I noticed that some of the ship’s crewmembers, especially those with children, were beginning to feel depressed. The ship’s master chief warned us about the doldrums. Being new to the Navy, I wasn’t sure what the doldrums were. I imagined some sort of flying fish coming out of the water and randomly hitting crewmembers on watch in the dead of night.

The doldrums actually refer to the convergence of the trade winds near the equator. This results in a shifting belt of dead calm to light breezes. The trade winds were named for their ability to quickly propel trading ships across the ocean. However, when these sailing ships entered the doldrums, they stalled, causing distress among the crews.

The doldrums are usually located between 5 degrees south and north of the equator. This area is also known as the Intertropical Convergence Zone. Depending on the season, and the amount of solar energy received, the zone can actually move 30 degrees north or south of the equator.

Near the zone, the sun’s direct radiation heats the air near the ocean’s surface, making it lighter and causing it to rise. The stillness of this rising air on the horizontal plane can cause sailing ships to go dead in the water for days on end.

Also, as this warm and moist air mass rises, it gives birth to some of the most intense convectional storms on earth along with the world’s heaviest precipitation. On one hand, the storms provided much-needed freshwater for the sailing ships caught in the doldrums but also probably added to the depression of the ships’ crews.

Further northward and southward are the horse latitudes that lie between 30 and 35 degrees from the equator. This is a region of strong high pressure and subsiding dry air that often results in only light to gentle winds across the seas. As in the doldrums, sailing ships becalmed in these waters would see their voyage time greatly extended.

Folklore states that sailors stuck in the horse latitudes would throw their cargo of dead or dying animals overboard to preserve precious water.

A more likely explanation for the term is that it derived from the “dead horse” ritual of sailors. In this ceremony, the seamen would parade a straw-stuffed effigy of a horse around the deck before throwing it overboard to celebrate having worked off the “dead horse” debt. Seamen were paid partly in advance before a voyage, and by the time they reached the horse latitudes, their debt was paid.

Today’s forecast

A vigorous cold front passed the Central Coast early Saturday morning with gusty southwesterly winds. These winds produced in a great amount of orographic enhancement along the Santa Lucia mountains.

Rainfall amounts along the Pecho Coast (Diablo Canyon nuclear power plant) recorded three- quarters of an inch of rain, while locations in western Atascadero recorded up to 3.5 inches.

A 1,001-millibar low- pressure system and associated cold front will pass the Central Coast on Monday morning with moderate rain and strong to gale force (25- to 38-mph) southerly winds.

Rain will spread east and south tonight over the Central Coast before the second weather impulse shifts the precipitation further south Monday morning. Snow levels are forecast to remain near 6,000 feet. Rainfall amounts should range from 0.50 to 1.50 inches with higher amounts in coastal mountains. Skies will clear late Monday.

The surface charts and models are indicating a strong Eastern Pacific high (1,030 millibars) developing off the California coast Tuesday. This condition will keep the storm track far to the north for another extended dry spell.

A pattern of moderate to fresh (13- to 24-mph) winds with higher gust northeasterly (offshore) winds developing during the night and morning hours, shifting out of the northwest during the afternoon hours, will begin Tuesday and will continue through next weekend. This cycle will give cool mornings and mild and sunny afternoons.

Additionally, there are increasing chances for ground fog during the night and morning in the coastal valleys and especially in the North County beginning Tuesday through next weekend.

The northeasterly (offshore) winds will be especially strong with gust up to 40 mph in the coastal canyons and passes, eastern San Luis Obispo near Cal Poly and French Hospital Medical Center and areas surrounding Morro Bay High School during the morning.

Today’s surf report

This morning’s 11- to 13-foot west-northwesterly (290-degree deep-water) swell (with an 11- to 14-second period) will gradually decrease to 8 to 10 feet (with a 12- to 14-second period) by tonight.

This 8- to 10-foot west-northwesterly (290-degree deep-water) swell (with a 12- to 14-second period) will remain at this height and period through Tuesday.

Combined with this west-northwesterly swell will be 4- to 6-foot southwesterly (210-degree shallow-water) seas late tonight into Monday.

A 6- to 8-foot northwesterly (290-degree deep-water) swell (with an 11- to 14-second period) is forecast along the coast Wednesday through Friday, decreasing to 5 to 7 feet on Saturday.

Preliminary extended surf analysis:

This morning’s surface charts and models are now indicating a strong Eastern Pacific high developing off the coast next week. This condition will keep the storm track far to the north. Consequently, only medium-height swell events are forecast over the following two weeks.

Seawater temperatures

Seawater temperatures will range between 54 and 56 degrees through Friday.

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John Lindsey is a media relations representative for PG&E. He is also a local weather expert and has lived along the Central Coast for nearly 26 years. To subscribe to his daily weather forecast or ask him a question, email pgeweather@pge.com.

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