Three Named Storms Are Hitting North America at the Same Time

Three named storms are swirling across North America at the same time this weekend, which is very unusual. Hurricane Isaias is pushing into the United States through the Gulf of Mexico. Meanwhile, two storms in the Pacific Ocean — Hurricane Simon and Tropical Storm Rachel — are moving toward Mexico and the American Southwest. Millions of people are preparing for strong winds, flooding, and heavy rain.

Hurricane Simon grew into a full hurricane on Thursday and has been moving along the western coast of Mexico. Weather computers used by forecasters mostly agree that Simon will turn toward the shore, but the exact spot where it hits could change. A small shift in its path could mean it makes landfall anywhere from Saturday night to early next week. No matter exactly where it lands, Simon will be close enough to the coast to bring dangerous winds, storm surge, and heavy rain. The longer it stays over warm ocean water, the stronger it will stay before it weakens over land.

Simon is part of a string of fast-growing Pacific storms this year, and much of the reason is El Niño — a natural weather pattern that warms parts of the Pacific Ocean. If Simon reaches Category 5 strength, it would be the fourth Category 5 hurricane in the Eastern and Central Pacific in a single season, joining storms named Genevieve, Lowell, and Polo. The water near these storms has been nearly 88 degrees Fahrenheit, which is about 3.5 degrees above normal. Warmer water gives hurricanes more energy to grow stronger and faster.

El Niño changes weather patterns all around the world in different ways. It usually slows down hurricane activity in the Atlantic Ocean, but it does the opposite in the Eastern Pacific — it actually helps storms grow stronger there. Scientists also note that ocean temperatures around the world have been rising for years, partly because oceans soak up extra heat trapped in the atmosphere by greenhouse gases. Researchers are still studying exactly how climate change affects El Niño.

Farther north, Tropical Storm Rachel is being watched closely by people in Southern California, who have been dealing with a dangerous heat wave. The storm is expected to move over northern Baja California late Saturday or early Sunday, and its center could pass very close to the U.S.-Mexico border. Kyle Wheeler, a meteorologist with the National Weather Service in San Diego, said on Friday that Rachel's path is still uncertain, but some of its effects will likely reach Southern California. Recent weather models show the storm may be tracking a little farther north than first expected.

If Rachel moves more to the north, the San Diego area could see widespread rain and wind gusts of 39 miles per hour or more. Lower areas could get up to one to two inches of rain, with higher totals in the mountains. On Saturday, thick clouds from Rachel could lower temperatures across Southern California by about 10 degrees compared to Friday, bringing some relief to people suffering through the heat wave. Cooler temperatures and cloud cover are expected even if the storm does not make a direct hit.

Mr. Wheeler said it is very rare for a Pacific tropical storm to make landfall in Southern California, and a direct impact only happens once every few years. The last major storm to hit the area was Tropical Storm Hilary in 2023, which had been a hurricane before it weakened. However, Mr. Wheeler said Rachel is not expected to be as strong as Hilary was when it arrived. Rachel is forecast to stay a strong tropical storm when it reaches land, then weaken quickly as it moves into the southwestern United States and becomes a weaker low-pressure system.