SAN DIEGO — With less than 24 hours before Hilary is expected to hit California as a tropical storm, here’s the current impact for San Diego County based on the storm’s projected trajectory.

At 8:30 p.m. Saturday, the National Hurricane Center determined that Hilary is a Category 1 storm. Meteorologists say it will still likely move over southern California — and San Diego — as a tropical storm early Sunday into Monday.

According to state and local officials, flooding will be the highest threat to residents when the storm hits, due to excessive rainfall stretching from the coast to the deserts.

Currently, all of Southern California is under a Tropical Storm Warning, given the likely development of tropical storm-force winds. The entire region is also under a Flood Watch through Monday.

San Diego officials are urging residents to avoid all unnecessary travel and shelter-in-place.

As of 9 p.m. Saturday, Hurricane Hilary remains off the southern Baja California coast and will move northward Saturday night into Sunday while picking up speed.

The main impacts will occur Sunday as the system moves into the county and tracks north. San Diegans should expect stronger winds and heavy widespread rain as early as Sunday morning into the evening hours. This will likely taper off into the overnight hours.

According to the National Weather Service, bands of heavy rain could potentially produce “dangerous” and “catastrophic” impacts, particularly across the deserts and desert mountain slopes.

Mountain and desert communities are likely to see up to seven to 10 inches of rain accumulate from Sunday into Monday. Meanwhile, coastal communities are likely to see about one to two-and-a-half inches of precipitation. Rain in valley areas is likely to reach up to two inches.

Winds will be strong as well. Farther north near Oceanside, residents might see gusts near 50 miles per hour. Southern coastal communities in San Diego County are forecasted to see gusts anywhere from 35 to 40 miles per hour.

Mountain and desert areas are likely to see the fastest wind speeds, reaching upwards of 65 to 70 miles per hour Sunday into Monday. Valleys will also see quicker wind speeds, with gusts around 40 to 50 miles per hour.

A high surf advisory has been issued for coastal Orange County, with sets up to eight feet.

A beach hazard statement has been issued for San Diego County beaches as waves are anticipated to reach heights of up to six feet. The highest waves are likely to be seen north of Carlsbad.

San Diego residents should expect dangerous swimming conditions and strong rip currents with the onset of Hilary.