Rainfall rates may reach rates up to half an inch per hour, forecasters predicted. Expected precipitation totals are 0.6 to 1.25 inches along the coast and in the valleys, 1 to 3 inches in the mountains and less than half an inch in the deserts.
The influx of moisture added to precipitation the county got last week could cause flooding and landslide risks in some areas, particularly in such old burn zones as the site of last spring's Cocos Fire near San Marcos, the NWS advised. The agency scheduled a flash flood watch for valley areas from 3 a.m. Friday to 3 a.m. Saturday.
The storm is also expected to affect local beaches, with larger than normal surf. A beach hazards statement for high surf is in effect through late tonight and a more serious high surf advisory is scheduled from 4 a.m. Friday to 10 p.m. Saturday.
The NWS said sets of 12 to 14 feet are possible with this storm, especially along west-facing beaches.
In the mountains, up to four inches of snowfall is possible on the county's highest peaks, according to the NWS, which said less than 2 inches are likely just below 6,000 feet.
Sunny skies are expected to return to the region this weekend.