REGION — The heaviest rainfall from a powerful storm system is expected to soak San Diego County today and could trigger flooding, according to the National Weather Service.
The NWS issued a flash flood watch that will remain until this evening throughout the county. A wind advisory will remain in effect in the county mountains until 4 a.m. Saturday.
Rainfall rates today are expected to reach 0.50 to 1 inch per hour everywhere except desert areas during the peak of the storm, which will last from about 6 a.m. to 2 p.m., and could be higher than that during isolated thunderstorms, NWS meteorologist Miguel Miller said.
Moderate flooding of the San Diego River is expected from late this morning until early Friday morning near Fashion Valley and Mission Valley, according to the weather service. Moderate flooding is also expected during the same period for the Santa Margarita River near Camp Pendleton.
In a 24-hour period ending around 3 a.m. today, the highest precipitation tallies included 3.44 inches at Birch Hill; 3.12 in the Palomar area; 2.05 in Fallbrook; 1.75 in Oceanside; 1.65 in Pine Valley; 1.54 in Julian; 1.48 in Valley Center; 1.40 in Harbison Canyon 1.33 in Santa Ysabel; 1.28 at Mount Laguna; 1.1 in Carlsbad; 1.08 in Escondido; 1.05 in Ramona; 1.03 in Santee; 0.99 in Encinitas; 0.81 in La Mesa and Solana Beach; 0.74 near Poway and Fashion Valley; 0.59 at Montgomery Field and the Tijuana Estuary; 0.54 at Brown Field; and 0.51 at Lindbergh Field and San Ysidro, according to the weather service.
The highest precipitation total for the deserts were San Felipe, with 0.75 of an inch, 0.45 in Borrego Palm Canyon and 0.34 near Coyote Creek.
Coastal and inland-valley areas are expected to get anywhere between 1.5 to 2.3 inches of rainfall today while the mountains are forecast to receive between 5.5 and 7 inches of rainfall and between 1 and 3 inches is expected in the county deserts, forecasters said.
Snow levels will remain above 8,000 feet during the day, then drop to around 6,000 feet tonight, Miller said.
South-to-southwest winds of 25 to 35 mph, with gusts reaching 55 mph, are expected late this afternoon through this evening, according to the NWS.
The most steady and intense rain is expected this morning through early this afternoon. Then the storm will die down by this evening, Miller said.
A chance of scattered showers will return Friday evening and remain through Monday afternoon, the meteorologist said.