A flood watch will be in effect for all of San Diego County from Thursday evening through Friday evening as a slow-moving storm travels through Southern California.
The National Weather Service said rainfall over the next two days is expected to total .75 to 1.5 inches for the coast and valleys, 1 to 2 inches for the mountains, and up to an inch in the deserts.
“A storm will move through Southern California today and Friday bringing increasing showers later today, and periods of heavy rain and some thunderstorms tonight into Friday. Showers will taper off Friday night and Saturday,” the weather service said.
Highs Thursday will be 69 to 72 along the coast, 69 to 72 in the western valleys, 64 to 69 near the foothills, 54 to 63 in the mountains and around 70 in the deserts.
The agency forecast sunny conditions for Thursday morning, but warned, “don’t be fooled into thinking that the storm is fizzling. It’s gathering energy for the main blast later.”
There is a slight chance of lightning at the beaches through Friday. A west-northwest swell Thursday will bring elevated surf and a higher risk of strong rip currents.
The city of San Diego is making storm preparations and taking steps to prevent flooding.
Starting Monday, the city’s Stormwater Department began placing “no parking” signs in low-lying or flood-risk areas, cleaning storm drains and inlets with a history of debris buildup, and street sweeping to reduce trash and pollutants from entering waterways.
Throughout the rain, stormwater staff will be monitoring more than 46,000 storm drains citywide for any issues.
Updated at 3:30 a.m., Thursday, Dec. 21, 2023