Southern California is experiencing a unique blend of weather this week, starting with hurricane-related moisture and dangerous coastal conditions, and quickly transitioning to a heat wave that will bring triple-digit temperatures to some areas.
Intermittent rainfall, tied to Hurricane Marie, began pelting parts of the Southland on Sunday morning and was expected to continue throughout the day. However, the more immediate concern for residents near the water is the potentially dangerous surf and rip currents now affecting local beaches.
The National Weather Service (NWS) has a high degree of confidence that Hurricane Marie itself will remain well offshore, tracking northwest over the next several days. Despite its distance, the hurricane is sending a growing southerly swell and large waves toward the coast, particularly impacting south-facing beaches as the Labor Day weekend wraps up.
A high surf advisory and a coastal flood advisory are both in effect until 11 p.m. Tuesday for portions of the Los Angeles County and Orange County coasts. Forecasters are expecting large breaking waves of 6 to 10 feet for south and southwestern-facing beaches, with west-facing beaches seeing waves between 4 to 7 feet. These conditions will be accompanied by strong and dangerous rip and longshore currents.
Minor coastal flooding is also a possibility, stemming from a combination of the high surf and high astronomical tides. Vulnerable south-facing shores are particularly at risk, with Avalon, Long Beach’s Alamitos Peninsula, and Malibu identified among the areas of greatest concern. High tides will continue to increase through early next week, projected to exceed 7 feet by Monday. This combination of elevated tides and the south swell poses a moderate risk of coastal flooding in some areas.
The NWS emphasized the need for caution, stating that, with "huge crowds expected at the beaches for the Labor Day holiday, the emphasis for these statements is to alert the public to be extra careful in and near the ocean." Officials are also urging inexperienced swimmers to stay out of the water altogether.
Beyond the beaches, the hurricane's moisture is bringing increased humidity and cloud cover through the weekend, potentially keeping overnight temperatures in the 70s along southern coastal areas and coastal valleys where clouds persist. There's also a 5% to 15% chance of thunderstorms, mainly in the Los Angeles County mountains and urban areas. Any stalled or repeatedly developing storms could produce over a quarter-inch of rain in an hour, according to the weather service. Forecasters also cautioned that roads could become especially slick with any wetting rain due to oils accumulated during the dry summer months.
Los Angeles Mayor Karen Bass announced that her office is coordinating with the Emergency Management Department, Los Angeles Fire Department, Los Angeles Police Department, Los Angeles County Public Works, and other relevant city departments to ensure all personnel are ready to respond as needed.
As the unsettled weather from Marie's remnants interacts with an unusually active jet stream, conditions could linger into early next week. However, once the storm moves on, Southern California is in for another heat wave. Temperatures are expected to soar into the 90s in many areas beginning Monday, peaking Tuesday through Thursday with triple-digit highs in the warmer regions, before finally declining to more average levels next weekend.
SoCal residents can expect a quick pivot from caution at the coast to bracing for significant heat as the week progresses.
