Southern California Map Shows Which Cities Atmospheric River Will Hit First

National Weather Service (NWS) meteorologists are tracking an atmospheric river expected to batter southern California this week, and the service’s office in San Diego shared a map showing the arrival times of rain and wind on Monday morning.

California has faced a slew of atmospheric rivers this winter that have caused devastating floods and landslides. Another moisture-laden storm arrived in the Golden State on Sunday and is working its way south, with meteorologists expecting rain and wind from the storm to arrive in Orange County later on Monday and San Diego by late Tuesday night.

Atmospheric rivers are a “long, narrow region in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics,” according to the National Oceanic and Atmospheric Administration.

“So you want to know timing of the rain over the next few days, but only have 12 seconds to spare? Well you’re in luck!

“Simulated radar and winds in the video below! Most impacts today will occur from Orange County northward, with rain arriving in San Diego later tomorrow. #CAwx” the NWS office in San Diego posted on X, formerly Twitter, on Monday.

The radar simulation shows precipitation creeping toward Los Angeles as of mid-Monday morning local time. The storm fully encompasses Los Angeles and Long Beach by Monday evening, where it stalls for more than 24 hours before creeping further south in the early morning hours on Wednesday.

NWS meteorologist Brian Adams told Newsweek that rain is currently falling in LA County, Santa Barbara and up through the Central Valley. The expansive system is slow moving, and Adams said that the rain won’t reach San Diego until Tuesday night or Wednesday morning.

However, Adams doesn’t expect the rain to be as torrential as a storm that brought devastating floods to San Diego in late January. Rainfall from the current storm could fall at rates of up to .75 inches per hour, whereas the January storm produced rainfall rates of up to 2 inches per hour.

Numerous storm warnings are in place throughout the state as of Monday, according to the NWS website. A wind advisory, special marine warning, flood warning and winter storm warning encompasses the northern half of the state as the southern half of the state faces flash-flood warnings, flood advisories and winter weather advisories.

A flood advisory issued in the Los Angeles area warned of minor flooding, particularly in low-lying areas or those with poor drainage.

“Some low-water crossings may become impassable,” the warning said. “Ponding of water in urban or other areas is occurring or is imminent. Shallow landslides consisting of rock and mud will also be possible.”