Hurricane Kay Veers Close to Baja California’s Western Coast

A storm that formed off the Pacific shores of Mexico is moving up the coast of the Baja California peninsula and threatening to bring unstable weather closer to California, which has already been coping with extreme heat and drought this summer.

Hurricane Kay was expected to hit Mexico’s west coast beginning on Thursday, the National Weather Service said.

There could be “life-threatening surf and rip current conditions,” winds nearing 85 miles per hour and up to 15 inches of rain for the Baja Peninsula in northwestern Mexico that could lead to flash flooding and landslides, the National Hurricane Center said.

The storm, which began last weekend off the coast of Acapulco, has already peaked and been downgraded to a “minimal” Category 1 hurricane, said Brandt Maxwell, a meteorologist with the Weather Service in San Diego.

“Over time it’ll be farther off the coast, but it looks like it is going to kind of circle over the eastern Pacific,” he said. “It is already starting to move into cooler waters off the coast of Baja California.”

Kay is the closest hurricane to hover near Southern California in more than two decades, since Hurricane Nora in 1997, Mr. Maxwell said. He estimated that at its closest point, Kay could pass about 100 miles to the south of San Diego. The hurricane is expected to weaken and become a tropical storm by Thursday evening, he said.

As the storm veers closer to San Diego, winds and tropical moisture will both increase, the Weather Service said. Heavy rains are expected in the mountains and deserts, as well as rough seas off the California coast, Mr. Maxwell said, and there is a risk of flash floods in the San Diego area. He added that east winds and a “blanket” of moisture would also temporarily exacerbate the prolonged heat that most of the state had been experiencing this week, and that it could potentially fan wildfires. Rising humidity over the next few days is then expected to mitigate fire risk, he added.

Tens of millions of people in California were under excessive heat warnings on Thursday, according to Weather Service data. Scorching heat had fueled two major wildfires and threatened the state’s power grid. The temperature in Sacramento was 116 degrees on Tuesday, a new daily record for the city.

California has also been grappling with a worsening drought. In May, officials adopted emergency regulations requiring local agencies across the state to cut water use by up to 20 percent. The rules also prohibit the watering of ornamental lawns at businesses or commercial properties.

Though the Atlantic hurricane season, which lasts from June to November, began quietly, two tropical storms grew into hurricanes in recent days, and one was nearing the island of Bermuda. The season has been unusually quiet so far, Mr. Maxwell said, with only five named storms, including two hurricanes.

By comparison, the pace of the Pacific storm season has been more brisk. Eleven named storms have originated there, seven of which became hurricanes, Mr. Maxwell said.

Researchers have found that hurricanes have grown more intense over the past four decades, fueled by climate change. There were 21 named storms last year, following a record-breaking 30 the year before.