UPDATE: 2:01 p.m., Sept. 4, 2019:
A flash flood warning has been issued for southeastern San Diego County on Wednesday afternoon after receiving an inch of rain.
The National Weather Service issued the warning around 1:50 p.m. for Alpine, Mount Laguna, Cuyamaca Rancho State Park, Lake Morena, Potrero, Lake Cuyamaca and Pine Valley.
Doppler radar indicated thunderstorms are producing heavy rain across the warned area, according to the NWS. NWS radar also indicated a severe thunderstorm in Pine Valley with 60 mph wind gusts and penny-size hail. The storm is expected to cause damage to roofs, siding and trees.
Original story:
Muggy weather will continue Wednesday in San Diego County and thunderstorms will be possible in the western valleys, the mountains and desert areas.
A high-pressure system lingering over the southwest will cause hot and humid weather to remain in San Diego County until Friday, according to the National Weather Service.
The NWS issued a heat advisory that will last from 11 a.m. to 6 p.m. Wednesday in coastal areas and the western valleys, including Vista, Escondido, El Cajon and Poway.
Thunderstorms will be possible Wednesday afternoon in the western valleys, the mountains and the deserts, forecasters said.
The chance of measurable precipitation is 20 percent in the deserts and the western valleys and 40 percent in the mountains.
Thunderstorms will be possible again Thursday afternoon in the mountains and deserts.
High temperatures Wednesday could reach 93 degrees near the coast and inland, 96 in the western valleys, 100 near the foothills, 97 in the mountains and 113 in the deserts.
The NWS advised that those who work outdoors should avoid the midday sun, wear light, loose-fitting clothing and drink plenty of water.
A trough of low pressure will make its way inland across northern California on Friday, then move south on Saturday and Sunday, bringing drier conditions and a drop in temperatures over the weekend, forecasters said.