Los Angeles County is included in an updated flash flood warning issued by the National Weather Service on Thursday at 5:20 p.m. The warning is in effect until 9 p.m. “At 5:20 p.m., Doppler radar indicated thunderstorms producing heavy rain across the warned area.

As Los Angeles braces for its most powerful storm of the season, concerns of mudslides and debris flows in recently fire-hit areas have prompted evacuation warnings.

In Kearny Mesa, all eastbound state Route 52 lanes at Convoy Street were shut down for several hours so Caltrans workers could clear out clogged drains near the roads. Several miles away, Caltrans crews were at work clearing drains after multiple lanes of Interstate 805 at Balboa Avenue were flooded.

An incoming atmospheric river shows the potential for several inches of rain, following months of below average rainfall.