Southern California’s heat wave will continue to bake the region Thursday, but forecasters said increasing tropical moisture could add scattered showers or even a thunderstorm to the mix before significant relief arrives late in the weekend.
Extreme heat warnings remain in effect through 8 p.m. Friday across much of Los Angeles County.
In Orange County, extreme heat warnings will remain in effect through 8 p.m. Friday for the Santa Ana Mountains and foothills and inland areas including Santa Ana, Garden Grove, Anaheim, Fullerton and Irvine. A less severe heat advisory will be in effect in Orange County coastal areas.
Numerous temperature records were set across the area on Wednesday.
Downtown Los Angeles reached 98 degrees, tying the record for the date set in 1981. Lancaster heated up to 107 degrees, breaking the 1950 record of 106. Woodland Hills topped out at 111 degrees, breaking the record of 109 set in 1981.
Temperatures will remain well above normal, with highs potentially reaching 112 degrees in some of the hottest valleys and mountain areas. National Weather Service forecasters said additional cloud cover expected Thursday and Friday was unlikely to provide much relief because the clouds are associated with tropical moisture.
Even if temperatures dip slightly, increasing humidity could make conditions feel more uncomfortable, according to the NWS.
The tropical moisture is associated in part with what was Tropical Storm Iselle off the Baja California coast. An upper-level trough is expected to push the moisture over California through Friday, while a cluster of thunderstorms moving north from northwestern Mexico could also contribute to unsettled conditions, forecasters said.
Most of the region will likely remain dry, but there is a 15% to 20% chance of showers across the area Thursday and Friday. Any showers that develop will generally produce light rain with large drops, according to the NWS.
There is also a 5% to 10% chance of a heavier shower or thunderstorm.
“This is a classic low chance, potentially high impact scenario,” forecasters said.
The heat will continue to coincide with elevated wildfire danger in parts of Los Angeles County, where a red flag warning remains in effect until 3 p.m. Friday for the San Gabriel Mountains and the Golden State (5) and Antelope Valley (14) freeway corridors.
A beach hazards statement will also remain in effect through 11 p.m. Thursday along south-facing beaches of Los Angeles County due to elevated surf and dangerous rip currents generated by southerly swells from Tropical Storms Iselle and Julio.
Swell heights of 3 to 5 feet with periods of around 14 seconds are expected, according to the NWS.
Temperatures are expected to begin falling Saturday, although conditions will remain hot. More substantial relief is forecast Sunday and Monday as a large trough moves over the West Coast, pushes the high-pressure system responsible for the heat eastward and strengthens onshore flow, forecasters said.
Temperatures could fall below normal by Sunday or Monday, and the marine layer is expected to return to coastal areas and some valleys.
Forecasters are also monitoring the possibility of another surge of tropical moisture reaching Southern California during the middle to latter part of next week, although they stressed that confidence remains low.