Tropical Storm Mario Brings Heavy Rain to Southern California

San Diego, California — Moisture from the remnants of Tropical Storm Mario will peak on Thursday, leading to heavy rainfall in southern California, according to the National Weather Service (NWS). As the storm system moves north, areas in the mountains and deserts are expected to experience increased rainfall from late morning through early evening.

A flood watch is in effect for the mountains and deserts until 2 a.m. Friday, as meteorologists predict bands of thunderstorms in these regions. The impact of the storm became evident on Wednesday when heavy bursts of rain and lightning were recorded in the same areas. “One such thunderstorm was detected on Doppler radar around 1:30 p.m. over the deserts, then around 2:10 p.m., moving west over the mountains,” said meteorologist Greg Bledsoe.

Starting Thursday evening, the chances of showers and thunderstorms will gradually decline, according to the NWS, with activity expected mainly in the mountains and deserts on Friday afternoon. Friday is likely to be mostly dry, with only a slight chance for rain. Meteorologist Sheena Parveen noted that computer models indicate more tropical moisture may affect the area by the end of the weekend and into early next week.

Tropical Storm Mario, which reformed on Monday after weakening to a tropical depression last Friday, is expected to continue losing strength as it moves over cooler waters near Baja California, according to the National Hurricane Center in Miami. Weather forecasts suggest a greater than 50% chance of rain for much of Southern California, particularly between Los Angeles County and San Diego County.

Rain estimates for the coastal regions indicate less than half an inch, while inland areas are at risk of higher rainfall totals. Cities like Ventura, Los Angeles, Big Bear Lake, Riverside, and Palm Springs are projected to see the heaviest rainfall on Thursday. The weather office said, “Rain showers and thunderstorms will continue to move north and west tonight” through Thursday morning, with storms gradually shifting east on Thursday afternoon.