Weather Watch

SLO was just hit with some high winds. But where does Saturday’s storm rank all-time?

The Saturday morning storm that hit California’s Central Coast produced a peak wind gust of 67 mph at 5 a.m. on top of Hi Mountain at the Condor Lookout station.

The station is at 3,190 feet and is a refurbished U.S, Forest Service field research facility that now serves as a tracking station for the endangered California condor. Weather data from this facility can be viewed at www.sloweather.com.

If you move away from the Earth’s surface, wind speeds tend to increase. In fact, at a height of only 33 feet, the winds often move twice as fast as at the surface because of less friction with the ground.

The meteorological tower at Diablo Canyon reported peak southeasterly wind gust of 62 mph 3:45 Saturday morning.

Remember, even a small increase in wind speed can greatly increase the force applied to objects, such as the surface of the ocean, buildings or trees. For example, if you double the wind speed from 22 mph to 44 mph, you’re quadrupling the amount of force.

These vigorous winds stoked my curiosity: What were the strongest winds ever recorded along Central Coast. This is what I discovered.

In March 1995, a storm developed about 900 miles off the Central Coast and caused an intense cold front to stall over our area that tapped into a plume of subtropical moisture (atmospheric river) that stretched to Hawaii. The rain began to fall early on March 9 and continued through the next day, producing amazing 24-hour rainfall totals. They ranged from a low of 3.4 inches in Pismo Beach to 11.6 inches in Santa Margarita.

The stalled cold front was accompanied by whole gale-force to storm-force (55- to 73-mph) southeasterly winds in the coastal regions of San Luis Obispo County. San Simeon reported sustained wind speeds of 70 mph with gusts reaching 88 mph, while the Diablo Canyon meteorological tower reported peak sustained winds of 58 mph with gusts reaching more than 65 mph.

A storm developed off the Central Coast on Jan. 17-18, 1988. This major storm made landfall near Pismo Beach, where the surface pressure dropped to 979 millibars, one of the all-time low-pressure readings for our area. The strongest winds with this tempest occurred south of San Luis Obispo County at Platform Harvest, approximately 16 miles west of Point Conception out at sea, were it was reported that northwesterly winds reached a sustained speed of approximately 78 mph from the northwest.

The 1997-1998 El Niño was one of the strongest on record. In February 1998, the storm door swung wide open. The mid-latitude westerly winds at the surface and in the upper levels of the atmosphere dramatically increased and brought a series of storms that marched across the Pacific through California. Rain gauges throughout the Central Coast recorded rainfall nearly every day through Feb. 24. Overall, 15.6 inches of rain was recorded that month at Diablo Canyon.

An intense storm developed off the coastline on Feb. 3, 1998, and produced the strongest winds ever reported at Diablo Canyon. After reviewing the meteorological data, the highest average wind speed reached 63 mph at 11:15 p.m. on the night of Feb. 3, 1998, with a peak wind speed of 79.41 mph — a windy night indeed.

At about the same time, the NOAA Santa Maria marine buoy about 25 miles northwest of Point Arguello hit 50 mph sustained with gust to 63 mph, while the Point Arguello weather station reported 54 mph with gust to 70 mph at 11:00 p.m. The old Point San Luis buoy saw average wind speeds reached 54 mph with gust to 69 mph.

There have been two occurrences of confirmed tornadoes on the Central Coast.

The first occurrence happened on April 7, 1926. A Pacific storm from the west produced lightning that struck large oil tanks along Tank Farm Road. As a result, hundreds of whirlwinds formed, but wind speed data is not available from this event.

The second confirmed tornado happened on the morning of May 5, 1998, near Cal Poly. It had the strongest winds that I have ever experienced. About 5:40 a.m., the rain became heavy and the wind caused my windows to vibrate. At first, I thought it was the train going by. My anemometer was fluctuating between 60 and 70 mph, and the power lines around my home were beginning to arc. Looking out my window, tree branches began to break, and the wind caused debris to rotate in a counterclockwise direction. My anemometer reached 86 mph!

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 pgeweather@pge.com or follow him on Twitter: @PGE_John.
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