First Major Rain of the Fall Season Could Bring Flash Floods to San Diego

We can expect the first major rainfall of the season this evening, as the county will shift from rather warmer temperatures to rainy weather until Thursday morning. A flash flood watch for San Diego mountain, valley, and coastal areas has been issued during this time.

Temperatures are expected to drop by 20 degrees in the next three days, as a cold front from the north collides with tropical moisture from the south. “This sets the stage for widespread rain and areas of heavy rain with mountain snowfall,” according to the National Weather Service. 

This represents a drastic shift in weather, considering San Diego County was under a Red Flag Warning last week for severe dry conditions and strong winds that had the potential to cause devastating wildfires. Now, the storm system is accumulating near the U.S.-Mexico border, where it will spill over onto the coast and eventually into mountain and desert areas. Some Southern California areas are expected to get snow, though it’s unlikely for San Diego mountain areas.

According to NBC 7 Meteorologist Sheena Parveen, we can expect up to an inch or more of rain in the County, with the most significant rainfall occurring between Wednesday and Thursday. County officials are already taking appropriate measures to prepare for the storm, as the storm system is bringing with it the risk of thunderstorms and flash flooding. 

The county is offering free sandbags to residents in anticipation of flooding. Officials in Encinitas removed six trees that were classified as at risk of falling over in severe weather. Races at the Del Mar Racetrack were canceled out of concern for the safety of horses and jockeys.

The rainfall will bring the first major storm of the season, coming shortly after the National Drought Mitigation Center designated San Diego as “abnormally dry” to “moderate drought” in some areas for the first time since 2019. While the rainfall is expected to be heavy, it is not expected to bring San Diego County completely out of drought conditions.