Weather Watch

Could clouds obscure the Central Coast’s view of the eclipse? Here’s the forecast


Total solar eclipses occur somewhere on the face of the earth about every year and a half — but only once every 370 to 380 years for a particular location on the planet.

That makes them exceedingly rare if you don’t travel.

Unfortunately, cloudy skies can make these spectacles even more uncommon. In other words, if it’s overcast, you have to wait another 375 years to see one in your neighborhood.

On Monday morning, the new moon will be in direct alignment with the sun and Earth and will pass in front of our star, creating a total solar eclipse. The 60- to 70-mile-wide band of totality will block the sun’s light for several minutes as it travels eastward across a swath of the United States from Oregon to South Carolina. Due to the earth’s spherical shape, the 60- to 70-mile-wide umbra will sprint eastward at 2,900 mph at the West Coast, slowing to 1,500 mph by the time it reaches the East Coast. At the Central Coast’s latitude, Monday’s event will only cover approximately 65 percent of the sun.

But a thick marine layer could block even more of the sun’s energy.

So what will the forecast be for the eclipse? As of Friday, a trough of low pressure was forecast to develop off the California coastline Sunday into Tuesday that will lead to a dark and persistent marine layer that will obscure the partial solar eclipse in the coastal regions of San Luis Obispo and Northern Santa Barbara counties Monday morning.

The inland valleys should be clear at the peak of the solar eclipse. The partial solar eclipse will begin at 9 a.m., peaking at 10:15 a.m. and conclude at 11:40 a.m., with about 65 percent of the sun covered.

In Northern California, the eclipse will reduce the sun’s power by 85 percent with partly cloudy to mostly clear skies in the inland areas. Except for low clouds along the coastline, most of Oregon and Idaho should be clear. Sadly, clouds are expected to obscure the eclipse in the path of totality from Nebraska into South Carolina.

Another interesting fact about solar eclipses that wasn’t much of a concern several decades ago is the electrical generation from solar panels. In PG&E’s service territory that covers much of Northern and Central California, more than 300,000 of its customers use rooftop solar, that’s 25 percent of all rooftop solar in the nation.

PG&E forecasts the eclipse will create a potential drop off of 2,600 megawatts of solar energy supply across its service area. PG&E and the California Independent System Operator plan to replace that supply with other fast-ramping power sources, including abundant clean, renewable hydropower available after a banner rainy season.

“Solar eclipses are rare, but we deal with the equivalent of a total eclipse every night when the sun goes down. Even with so much of California’s energy now coming from solar, PG&E has a diverse supply of resources that allow us to meet customers’ needs for safe and reliable energy around the clock,” said Nick Stavropoulos, president and COO of PG&E.

PG&E also reminds people to take proper safety measures if they choose to watch the eclipse. Looking directly at the sun is unsafe, even during a partial eclipse. Eclipse viewers should use special-purpose solar filters, such as eclipse glasses or hand-held solar viewers purchased from authorized dealers of such products. Visit NASA’s website for more information on the coming eclipse.

John Lindsey’s column is special to The Tribune. He is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at or follow him on Twitter @PGE_John.

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