The Southland runs the chance of getting wet today, Thursday and Friday, including in thunderstorms that could trigger debris flows in areas denuded by wildfire and flash flooding, forecasters said.
A low-pressure system has been moving toward California’s southwestern coast from west of Baja California, “bringing a possibility of showers and thunderstorms to much of the area” today and Thursday, said a National Weather Service statement. “The thunderstorms will shift eastward to interior Los Angeles County on Friday and end late Friday evening.”
Only a slight chance of showers and thunderstorms threaten valley and coastal areas, but the chances of precipitation will be greater in mountain areas during afternoon and evening hours.
Any thunderstorm will have the potential to unleash heavy downpours because of moisture and atmospheric instability created by a southerly air flow preceding the low-pressure system, the statement said.
Any thunderstorm today will move quickly over the region thanks to a strong southerly flow, but as the flow weakens Thursday, “the flash flood potential will increase over the mountains and desert due to slower moving storms,” it said.
The heavy rainfall generated in such conditions will create “a risk of flash flooding and debris flows in recent burn areas,” it said.
NWS forecasters set the chance of precipitation at 20 percent today. Temperatures, meanwhile, will remain relatively high — generally the high 80s and low 90s.
The NWS forecast mostly cloudy skies today and highs of 79 in San Clemente; 81 in Avalon; 82 in Newport Beach, Laguna Beach and on Mount Wilson; 83 at LAX; 86 in Mission Viejo; 87 in Long Beach and Irvine; 88 in downtown L.A., San Gabriel and Anaheim; 89 in Fullerton; 90 in Burbank; 91 in Yorba Linda, Palmdale, Lancaster, Saugus and Pasadena; and 92 in Woodland Hills.
Thursday’s temperatures will be around 5 degrees lower in many communities and fall marginally on Friday.