"Departures to Los Angeles International are grounded due to thunderstorms," the FAA said in an earlier statement on its website.
According to the FAA's website, the ground stop was set to expire at 1 a.m. Saturday, but it appeared the order expired before that. An update from the agency said departures were being delayed at least 15 minutes.
The grounding applied to departures that covered portions of California, Nevada, Utah and Arizona.
Some flights destined for LAX were being diverted to the airport in Ontario.
Heavy rain was falling across Southern California as the storm system moved over the region, prompting high winds, flood warnings and evacuation warnings for some residents.
A Flash Flood Warning for Los Angeles County was extended until 2 a.m. Saturday.