UPDATE 5:27 p.m.: A photo by KPCC's John Rabe of flooding in the L.A. River. It surprised workers, ruining some smaller equipment.
UPDATE 4:49 p.m.: The National Weather Service issued a new flash flood warning for central Los Angeles County, with affected cities including East L.A., Huntington Park, Monterey Park and Montebello.
The alert was triggered by Doppler radar showing a cluster of strong and slow-moving thunderstorms over much of East L.A. and the San Gabriel Valley. The rain from these storms has been heavy, with some areas experiencing over two inches of rain per hour.
The flash flood warning is in effect until 6:30 p.m.
UPDATE 3:17 p.m.: A flash flood warning has been issued for central Los Angeles County by the National Weather Service. This was triggered by radar showing stationary thunderstorms with over an inch of rain per hour across the San Gabriel Mountains and foothills, meaning flash flooding is likely across the warning area.
According to the National Weather Service, people near the Station Fire burn area should be particularly alert for flooding and debris flows.
The affected cities include La Crescenta, La Canada Flintridge, Monterey Park, Tujunga, Sierra Madre, Lake View Terrace and Sunland.
The flash flood warning is in effect until 4:45 p.m.
Scattered showers and isolated thunderstorms are expected to continue through Thursday night throughout Southern California, with some showers lingering into Friday. Some areas may experience lightning, small hail and brief heavy rain through Thursday evening.
UPDATE 9:31 a.m.: Not much rain has hit the region so far. As of 9:00 a.m., the National Weather Service recorded 0.11 of an inch at Los Angeles International Airport, 0.04 in downtown and 0.26 in Avalon. Orange County is drier, with trace amounts of rainfall.
UPDATE 8:31 a.m.: Metro announced that the Blue Line has resumed normal service, with minor delays until 9:30 a.m. Those who need delay verification for an employer or school can call customer relations.
UPDATE 8:09 a.m.: There has been a loss of electrical power – due to possible lightning strikes to the overhead power system – affecting some Metro Blue Line rail service in Long Beach, says Luis Inzunza of Metro.
Twenty buses have been sent to shuttle passengers between the Willow, Wardlow and Del Amo Stations, Inzunza says. It is one of the most heavily traveled lines in the system.
PREVIOUSLY: A storm system moved into Southern California early Thursday, making for a wet commute for many in the region.
Rain has already fallen in western Los Angeles and Orange Counties, including Los Angeles International Airport, Long Beach and Newport Beach. Commuters can expect wet roads during the morning drive.
Showers and thunderstorms are forecast through late morning and more rain is expected into Thursday night.
Along with the rain, temperatures are expected to drop into the mid-60s along the coast and high-60s inland. The mountain areas may see temperatures dipping into the 40s.