LOS ANGELES, California — A slow-moving storm is bringing heavy rain, wind, and lightning to much of California this week, with the brunt of the system targeting Southern California from Wednesday through Friday. This storm has the potential to create travel disruptions and flash flooding ahead of the Christmas holiday.

The storm, part of a possible parade of storms on the West Coast this holiday season, is fueled by a strong El Niño weather pattern. A low-pressure system is spinning offshore, bringing moist, subtropical air over the region. Flood watches cover most of coastal Central and Southern California into Friday afternoon, with the National Weather Service warning of significant travel delays, road closures, and possible floods.

“This may actually have quite significant storm-related impacts in Southern California, with at least localized regions of very heavy rainfall and torrential thunderstorm downpours,” said Daniel Swain, a climate scientist at UCLA.

In addition to heavy rain, the National Weather Service in Los Angeles warned of a high risk of flooding, with 4 to 8 inches of rain possible in the higher terrain. The Weather Prediction Center issued a Level 3 out of 4 risk level for excessive rainfall for the area, where “numerous floods are likely,” including urban flooding and mudslides.

Despite the flood risk, the wet weather is welcome due to the dry start to the water year. Southern California is in need of the rainfall to catch up on the region’s water supply.

Meanwhile, the Sierra Nevada snowpack is off to a dismal start at just 33 percent of average and is experiencing a downward trend due to climate change. The heavy precipitation is expected to be concentrated more in the core winter months as California’s climate warms.

The Weather Service’s Climate Prediction Center mentioned the possibility of another round of storms in Central or Northern California next week, but models have been wavering, and it’s not certain which part of the West Coast will be impacted.

As the storm continues to bring heavy rain and potential flooding to Southern California, officials and residents are preparing for the impacts of this intense weather system.