Los Angeles is preparing for a week of substantial rainfall and potential flooding as a robust storm system advances into Southern California. The National Weather Service (NWS) forecasts between 2 to 4 inches of rain across the region, with even greater amounts anticipated in the foothills and mountainous areas. This weather pattern is attributed to a significant atmospheric river event, known for carrying substantial moisture from the Pacific Ocean. Residents are strongly advised to prepare for wet conditions and potential disruptions caused by the heavy rain.