Storm Brings Hail, 47-Foot Seas Offshore, and a Dangerous Night of Surf to the North Coast

FORT BRAGG, Calif. — A powerful storm swept onto the North Coast on Friday, bringing hail to Shelter Cove, steady rain to the Mendocino coast, and a large swell that forecasters say will make for a hazardous night along the shoreline.

A severe thunderstorm near Shelter Cove prompted a warning from the National Weather Service in Eureka shortly before 1 p.m. One resident shared a photograph of 2-inch pieces of hail with the meteorologists.

Far offshore, Buoy 46002, about 275 nautical miles west of Coos Bay, Ore., recorded 47-foot waves around 4 p.m. By 8 p.m. the same buoy was reporting seas of about 30 feet.

Meteorologist Edward Swafford said the 4 p.m. reading came during the most energetic stretch of the swell, which is now headed for shore. “We are predicting a large swell to hit our area overnight,” he said. “Overnight will be really dangerous, really hazardous.” When the swell backs off, he said, waves will still be about 20 feet.

The Weather Service has a high surf warning in effect for southwestern Humboldt and coastal Mendocino counties until 4 a.m. Sunday, calling for dangerously large breaking waves of 30 to 40 feet. Forecasters warn the waves can sweep people off jetties and docks, cause significant beach erosion, and behave erratically. Mariners are urged to use extreme caution crossing the bar or stay in port. After only a brief improvement late Saturday through Sunday, a second large swell is forecast late Sunday through Monday.

Rain began between 4 and 5 a.m. Friday. Swafford said Fort Bragg had picked up 1.2 inches and Mendocino 1.54 inches since then. Rainfall amounts are “one of the more difficult things to nail down,” Swafford said, but he was pleased with how closely the forecast matched what came.

The storm is part of a larger pattern. A strong low-pressure system, which Swafford described as strongly cyclonic, is churning in the eastern Pacific. Ahead of it, a series of troughs, elongated areas of low pressure, is arriving in waves. “The waves are outrunning the storm itself,” Swafford said. The system weakens as it moves inland.

The next front should reach the North Coast around 10 or 11 p.m. Saturday, a little weaker in rain intensity, Swafford said. The Weather Service’s marine forecast for Oregon and Washington waters similarly shows a strong cold front arriving late Saturday, a trough late Sunday into Monday, and another frontal system Tuesday.

Swafford expects fog late Monday night into Tuesday morning, with another wave of rain Tuesday late afternoon. A ridge of high pressure, possibly an omega block, could follow around Friday, Nov. 20.

The Weather Service’s wave model shows swell off the southern Mendocino coast building to about 21 feet around midnight Friday, with waves roughly 18 seconds apart, and staying near 20 feet until early Saturday. It then eases to about 18 feet by midday Saturday, dips late Saturday into Sunday, and builds again to about 17 feet Sunday night.