The showers should be over by Thursday morning and Orange County residents can look forward to a dry New Year's Day, according to the National Weather Service.
A quarter-inch to a half-inch of rain will douse the region, but winds and cold temperatures are the real elements to watch.
The average high historically for this week at John Wayne Airport is about 66 degrees. Thursday's highs will be in the mid-50s.
Also, lows are taking a dip as well with temperatures in the upper 30s, compared to the upper 40s average from last year.
Wednesday's storm wreaked havoc on local streets.
Three people were sent to the hospital following a two-car crash in the morning rain on the southbound San Diego (405) Freeway at Harbor Boulevard, authorities said.
About 6:23 a.m. a car spun out of control in the carpool lane, coming to a rest facing the wrong way. A second vehicle didn't have time to stop and slammed into the first car head-on, said California Highway Patrol officials.
Authorities had no details on who the passengers were or the extent of their injuries. One person was sent to Western Medical Center's trauma center in Santa Ana, another was sent to UCI Medical Center's trauma center and a third person was sent to a local hospital, officials said.
A SigAlert was issued for about an hour.
Later in the afternoon, a train crossing on Sunflower Avenue between Harbor Boulevard and Susan Street malfunctioned for about an hour. Police said the arms of the train crossing were stuck in the down position, creating a line 15 to 20 cars long at one point on either side of the crossing.
Maintenance workers from Union Pacific railroads eventually came out and fixed the problem.
The rain did not dampen the enthusiasm of a group of about 300 students from around Orange County, including 15 from Orange Coast College and Estancia High School in Costa Mesa. They travelled by charter bus from Irvine to Pasadena, where they spent the day decorating floats that will appear in Saturday's Rose Parade.