Last Wednesday, a large sunspot turning away from Earth unleashed a huge eruption of highly charged particles, mainly protons and electrons that traveled away from the sun at extreme speeds.
Earth was not in the line of fire, but if it had been, this exceptionally large and fast-moving group of energetic particles would have hit the planet’s magnetosphere and probably produced an aurora of such intensity that it might have been seen as far south as the Central Coast.
Typically, the aurora, also called the northern/southern lights, is seen in the far northern and southern latitudes of the Earth — greater than 50 degrees of latitude. In the Northern Hemisphere, the lights are referred to as the aurora borealis, and in the Southern Hemisphere, it’s the aurora australis.
However, during the dark hours on Aug. 12, 2000, when the Perseids meteor shower was at its peak, countless sky gazers throughout California reported seeing the northern lights. Not unexpectedly, many found it difficult to look away from the dazzling aurora borealis in the northern sky to watch for meteors streaking overhead.
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I spent two summers mining for gold back in the mid-1970s in Chicken, Alaska, but never saw the northern lights. That’s because of the perpetual twilight from late May through August — it never really got dark enough to see the lights. It wasn’t until I was on a cross-country flight, on a U.S. Navy P-3 Orion to Alaska in December 2003, that I was finally able to see this amazing sight.
I and my fellow aircrew were walking back to the barracks after having dinner at the Elmendorf Air Force Base dining facility near Anchorage on a bitterly cold night. I remember our navigator saying, “Look at that!” We looked up and saw a moving curtain of blue and green light across the sky. None of us could turn away from this eye-catching sight for the seven minutes that it lasted. According to folklore, the Eskimos thought the lights were from demons’ lanterns searching the heavens for lost souls.
The aurora is caused by different gases in the upper reaches of the atmosphere that emit different colors of light when excited by high-energy particles from the sun. Molecules of oxygen usually emit green or red light, and molecular nitrogen can give off violet light.
If you’re thinking about traveling north to see the aurora, it occurs most frequently around the spring and fall equinoxes (Sept. 22 and March 22) during the late night or early morning hours.
However, the northern lights are the most intense from December to March when nights are longer and darker. They are also brighter during a new moon.
The 1,026-millibar Eastern Pacific high will remain nearly stationary about 900 miles to the west of San Luis Obispo over the next 72 hours, while a thermal trough will persist over the Central Valley. This morning’s marine low clouds and fog will clear from the coastal valleys later this morning but will persist along the beaches for most of the day.
Today’s temperatures will range from the high 50s to low 60s along the northwesterly facing beaches (Los Osos, Morro Bay and Cambria) to the mid-60s along the southwesterly facing beaches (Avila Beach and Cayucos).
The coastal valleys (San Luis Obispo) will reach the low 70s, while the North County will range between the low to mid-80s.
A benign weather pattern will develop early this week, with extensive night and morning coastal low clouds and fog and below normal temperatures for mid-September. In general, temperatures will range from the 60s along the coast, the 70s across coastal valleys and the mid- 80s in the North County.
A somewhat deep Gulf of Alaska low-pressure system will begin to influence our weather late Wednesday, with fresh to strong (19 and 31 mph) northwesterly winds and a greater amount of sunshine along the beaches, especially the southwesterly facing ones. This system is expected to produce rain in Northern California, but the Central Coast will remain dry.
Today’s 3- to 4-foot northwesterly (300-degree deepwater) swell (with a 7- and 11-second period) will remain at this height and period through Wednesday morning. Increasing northwesterly winds will generate a 3- to 5-foot northwesterly (320-degree deepwater) sea and swell (with a 5- to 8-second period) Wednesday afternoon, increasing to 4 to 6 feet Thursday through Saturday.
Arriving from the Southern Hemisphere: A large storm 2,000 miles east of New Zealand produced 30-plus foot seas. Southwesterly (205-degree deepwater) swells from this storm will arrive along our coastline Thursday at 1 to 3 feet (with an 18- to 20-second period), building to 2 to 3 feet (with a 17- to 19-second period) on Friday. This swell will peak Saturday at 3 to 4 feet (with a 15- to 17-second period).
A very intense storm is forecast to develop in the Tasman Sea, a large body of water between Australia and New Zealand, with seas reaching more than 50 feet later this week. However, southerly swells from this area rarely ever reaches our coastline, and little effect is expected along the Central Coast.
Seawater temperatures will range between 53 and 55 degrees through Monday, increasing to 54 and 56 degrees Tuesday through Wednesday. Seawater temperatures will decrease Thursday through Saturday.
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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 more than 23 years. If you would like to subscribe to his daily weather forecast or ask him a question, send him an e-mail at pgeweather@ pge.com.