Flood Watch issued for parts of LA County by National Weather Service
The National Weather Service issued a Flood Watch starting at 11 a.m. Monday until Monday evening for parts of Los Angeles County.
The Flood Watch is in effect for Los Angeles County mountains and the Antelope Valley. Palmdale, Acton, Mount Pinos, Mount Wilson, Lockwood Valley and Lancaster will be affected.
The northeast portion of the Bobcat burn scar in the eastern San Gabriel mountains is under flood watch until 3:15 p.m. Monday, the National Weather Service said.
Far eastern LA County, including Big Pines and Llano is under flood watch until 4:15 p.m. Monday, the National Weather Service said.
A flood advisory is in effect for Central Los Angeles County until 4:30 p.m. Monday. Heavy rainfall could trigger shallow debris flows in and near recent wildfire burn scars. Some low-water crossings may become impassable.
Record rainfall was reported in Palmdale and Sandberg on Sunday. Palmdale Airport recorded 0.46 inches of rain, breaking a record of 0.23 inches set in 1976. Sandberg recorded 0.32 inches of rain, breaking a record of 0.31 inches set in 1976.
Excessive runoff could result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Mud and debris flows are possible around recent burn areas, the NWS says.
There is a chance of showers and thunderstorms from late Monday morning until Monday evening. Some storms and bursts can produce heavy downpours with rainfall rates exceeding 1 inch per hour.
Sunday evening, the National Weather Service issued multiple Flash Flood Warnings for Southern California for San Bernardino, Riverside, Lake Arrowhead, and Lake Elsinore, among other regions as rain and mudslides came into the area. Those warnings expired.
Downpours on Sunday night led to mudslides in the Lake Hughes area that inundated dozens of vehicles and trapped as many as 50 people who had to be rescued by county fire crews. Some roads in the area were still blocked on Monday afternoon.
"Thunderstorm activity is expectedly quite heavy across the mountains and Antelope Valley today (Monday) with ample moisture and instability lingering after Kay's departure," according to the NWS. "Storms are also very slow moving so any storms that do develop tend to stay put for quite some time increasing the threat of flooding. Storms may not be confined to the mountains as there is some instability at lower elevations."
Forecasters said the unstable weather will continue through the evening.
Conditions were expected to return to normal by Tuesday.