Triple digit heat with high humidity is expected again Thursday in the Inland Empire and thunderstorms will be possible throughout Riverside County.
The National Weather Service issued a heat advisory for the Riverside metropolitan area that was originally set to expire at 6 p.m. Wednesday, but was extended through 8 p.m. Thursday.
Thunderstorms will be possible throughout Riverside County Thursday afternoon, NWS meteorologist Miguel Miller said.
The chance of measurable precipitation is 20 percent Thursday in the Riverside metropolitan area and the Coachella Valley, 40 percent in the San Gorgonio Pass near Banning and 50 percent in the mountains.
The NWS issued a flash flood watch that will be in effect from noon Thursday through this evening in the San Gorgonio Pass near Banning and the mountains.
The high pressure system that has been the driving force behind the hot, sticky and unstable conditions this week will make its way east on Friday and give way to a trough of low pressure moving in northern California, Miller said.
Thunderstorms will be possible again in the mountains Friday afternoon, but conditions will be cooler and drier throughout the county by Sunday.
High temperatures Thursday could reach 107 in the Coachella Valley and the San Gorgonio Pass near Banning, 101 degrees in Riverside, 94 in Temecula and 100 in Hemet.
The NWS advised that those who work outdoors should avoid the midday sun, wear light, loose-fitting clothing and drink plenty of water.
Cooling centers are open daily across the county, providing residents who do not live in climate-controlled environments a free, cool space to relax until the evening hours.
A complete list of cooling centers is available at www.capriverside.org/Portals/0/PDF/Cool/2019_Cool_Center_Directory_7_10 _2019.pdf.
A brush fire possibly triggered by lightning sparked just west of Murrieta Wednesday afternoon and prompted evacuations.
As of about 9 p.m. Wednesday, the blaze had burned 994 acres and evacuations had been issued for all residents on The Trails Circle and in Copper Canyon, south of Calle del Oso Oro between Clinton Keith and Murrieta Creek.
The Murrieta Valley Unified School District announced Wednesday night that all of its schools will be closed Thursday.