California, a state that has historically been spared from hurricane landfalls, is facing an increased possibility of experiencing a major storm this year, according to AccuWeather Senior Meteorologist Paul Pastelok. He has identified three critical atmospheric conditions that are converging due to a powerful El Niño, potentially enabling a hurricane to form in the Pacific and make its way to the California coast.
The first necessary condition is exceptionally warm ocean water between Mexico and the Baja California Peninsula. Pastelok noted that current sea surface temperatures in this region are significantly above average, describing it as a "marine heat wave." This warm water acts as fuel for tropical cyclones, allowing them to maintain or increase their intensity. AccuWeather's forecast suggests this El Niño could be one of the strongest on record, with Pacific Ocean surface temperatures potentially rising by 4.8°F (2.66°C), a level often termed a 'Super' El Niño. These elevated temperatures are expected to persist through the end of 2026.
The second crucial element is a weather pattern that can guide a tropical storm northward towards California. Typically, storms in this region either dissipate or veer westward towards Hawaii. However, Pastelok explained that weather systems moving south from the Pacific Northwest can act like a "giant vacuum cleaner," creating a pull that can draw these storms towards the California coast. He observed that such systems have been observed moving into Western California periodically, increasing the likelihood of a storm being directed inland during the late summer.
Hurricane Marie, which formed near the coast of Mexico on September 2, is one such storm whose trajectory is being closely monitored. Spaghetti models, which track potential storm paths, show multiple scenarios where Marie could move east and make landfall between San Diego and Los Angeles in early September.
The third ingredient identified by Pastelok is calmer upper-level winds in the eastern Pacific. High wind shear, where winds at different altitudes blow at varying speeds or directions, can tear apart nascent storms. The current 'Super' El Niño is predicted to reduce this wind shear in the Eastern Pacific, allowing tropical storms to develop and strengthen more readily, potentially growing into major hurricanes.
Historically, the California Current has brought cooler waters to the coast, and prevailing northeast trade winds have steered weather systems westward. However, the current conditions are altering these dynamics. The last time a tropical cyclone officially made landfall in California was Hurricane Nora in 1997. This storm weakened significantly before crossing from Mexico into the U.S. on September 25, 1997, bringing rain, rough surf, and slick roads to Southern California. It caused traffic fatalities and widespread power outages in the Los Angeles area.
Even if a direct hurricane landfall is avoided, Pastelok warned that the moisture from these powerful Pacific storms could still cause significant damage through flooding and mudslides in California and other Southwestern states like Arizona and New Mexico. The remnants of Hurricane Hilary in August 2023, while not a direct landfall, caused considerable flooding and power disruptions in Southern California, underscoring the potential impact of tropical moisture even in weakened systems.
