Surface ocean temperatures along California, including the northern and central coasts, are rising to “record-shattering” numbers partly due to this winter’s “extreme El Niño,” a climate scientist said in a webinar Thursday.
Massive waves and rainy weather were also expected to begin Friday in the Bay Area after a relatively dry November so far.
“Even though it has not yet rained at all in places like San Francisco, believe me, it will, and it will probably rain quite a bit in the coming days,” said Daniel Swain, a scientist in the California Institute for Water Resources within the University of California’s Agriculture and Natural Resources division.
Swain has been monitoring oceanic temperatures ahead of this year’s El Niño, a temporary warming of the tropical eastern Pacific Ocean that can lead to significant climate events around the world. He publishes graphs and analyzes data to make weather predictions on his blog and YouTube channel “Weather West.”
This week, something “extraordinary” has happened in the ocean off the West Coast, all the way from Mexico to Northern California, Swain said. A “marine heat wave” has caused surface ocean temperatures along the coast to rise to “astonishing” numbers that are breaking records, he said.
“There is a region, all the way from about Ensenada, Mexico, northward to about Sonoma County coast, essentially, that is contiguously more than 10 degrees Fahrenheit above average,” Swain said. “We have never seen that before at any point in recorded history in California.”
The Scripps Institution of Oceanography at the University of California, San Diego, has a “Shore Stations Program” where it records oceanic temperatures at several spots along the California coast, including a station near the Farallon Islands off the coast of San Francisco.
Waters near the Farallon Islands have measured about 10 degrees Fahrenheit higher than average November temperatures in recent days. The average temperatures this week in November are around 56 degrees. In the last few days, the temperature has reached around 66 degrees.
“We’re starting to get off the charts,” Swain said. “This is pretty extraordinary.”
The extremely high oceanic temperatures can lead to a higher risk of wetter storms, lightning and thunder, higher tides than normal, and disruptions to marine species that aren’t used to such warm temperatures.
That abnormal warmth, Swain said, can elevate the risk of thunder and lightning storms this weekend in the Bay Area as the first significant El Niño storm is expected to begin Friday.
In San Francisco, Swain expects the next few weeks to bring about 2.5-4.5 inches of rain even though it has been relatively dry so far this month.
“Expect a pretty high impact cold frontal passage tomorrow morning in the Bay Area, maybe into the afternoon,” he said. “I fully expect November will probably end up being a wetter than average month, essentially statewide.”
More flood concerns loom over holidays
The National Weather Service has also announced coastal hazards this weekend for the coast from Mendocino County down to Monterey County. Dangerously large breaking waves and high surf are expected from Friday to Sunday. Advisories for coastal flood risk and hazardous beach conditions are in effect through Friday.
“There are going to be enormous waves along the Northern California coast beginning this weekend that could actually be very problematic, very dangerous if you’re out there on the beach,” Swain said.
Interactive map shows areas along the San Francisco Bay shoreline at risk of flooding from rising sea levels and storm surges. (Adapting to Rising Tides Program/San Francisco Bay Conservation and Development Commission)
Bayside flooding due to the high tide and storm surge is also expected this weekend. Additionally, the first round of king tides is expected to hit in late November. King tides are exceptionally high tides that occur during a new or full moon.
“I’m still very concerned, frankly, about what’s going to happen around the Thanksgiving holiday and then again around the late December holidays during the king tide windows,” he said.
The San Francisco Bay Conservation and Development Commission is providing informational resources for the public. Bay Area residents can also sign up for emergency alerts by searching for their region.
