Warm and humid weather gave way to storms in parts of the Southland Thursday, prompting flood watches and warnings as rain and hail began battering some communities in the northern reaches of the county.
Despite dire weather warnings for outlying parts of Los Angeles County, areas from downtown to the westside remained clear, with blue skies broken only by billowing clouds in the distance.
The National Weather Service issued flash flood warnings for the northwestern and north-central portions of Los Angeles County early this afternoon, affecting areas such as Acton, Santa Clarita, Palmdale, Gorman, Pyramid Lake and Castaic, as well as the Antelope Valley (14) Freeway corridor.
Forecasters said radar showed a storm producing heavy rain across the area, and noted that “flash flooding is expected to begin shortly if not already occurring.” They also warned that the storm could produce lighting, small hail and gusting winds.
The flash flood warnings will remain in effect until 4:45 p.m., although it will be in effect until 5:45 p.m. in northwestern Los Angeles County and until 6:15 p.m. for areas such as Wrightwood and Pearblossom. A less-serious flash flood watch was issued earlier affecting most of the county, and that will remain in place until 8 p.m.
The California Highway Patrol reported flooding on the 14 Freeway in the Acton area, as well as at the intersection of Escondido Canyon and Ward roads.
Heavy rain and hail battered motorists on the freeway, prompting some to stop and take cover beneath a freeway overpass.
Forecasters noted earlier that “due to the deep moisture in place,” any storms that develop could bring heavy rainfall and raise the danger of flooding.
According to the NWS, the best chances for storms will be over the mountains and deserts, “but there will even be the possibility of thunderstorms over coastal and coastal valley areas.”
“In the mountains and deserts, the storms could be intense enough to generate flash flooding,” according to the Weather Service. “Mud and debris flows are possible near the recent burn area, including the Colby and Pine burn areas.”
Glendora city officials were monitoring the forecast near the Colby fire burn area, but they did not immediately impose any parking or other restrictions — although they warned residents of the possibility of heavy rain. The city typically will raise its alert level to “yellow” if there is a threat of significant rainfall. The alert requires residents to remove vehicles and other large objects from streets to protect them from flooding and mud flows, and to ensure access for emergency crews.
Although the alert level had not been raised as of about mid-afternoon, forecasters said any storms that develop in the San Gabriel Valley area could bring up to 1 to 2 inches per hour of rain.
The threat of showers and thunderstorms will continue into early next week, forecasters said, including a “slight chance of afternoon and evening thunderstorms across the mountains of Los Angeles County and the Antelope Valley Sunday.”
Temperatures are expected to range from the mid- to upper-70s at the beaches Thursday, rising to the upper-80s inland and hitting the 90s in the valleys.
—City News Service