SoCal's Heat Wave Is Getting Even Worse: Hottest Week Of Year Forecast

LOS ANGELES, CA — The hottest week of the summer has arrived, igniting a heatwave that will bring soaring temperatures to Southern California, prompting health warnings and triggering fire danger in multiple regions.

It's a prolonged heat wave with no end in sight.

"We've got a pretty strong — especially for this time of the year — area of high pressure that is over parts of Southern California. Right now it centers more over New Mexico and Texas, but it's pretty broad, so we're kind of getting looped into that warmer air, and as we move into the middle and the end of the week, that high pressure system is going to begin to shift west so that we're more under its influence. That's why we're going to see our warmer conditions Wednesday, Thursday and Friday," said Casey Oswant, a meteorologist for National Weather Service in San Diego.

According to the National Weather Service, all areas 5 to 10 miles inland of the beaches will likely see high temperatures in range of 100 to 110 by Tuesday or Wednesday, with little change through Friday or Saturday. The daytime highs and overnight lows will be 8 to 12 degrees above normal, which will greatly exacerbate the heat risk as there will be no time for a person's body to release the heat stress.

The heat wave is expected to peak Tuesday through Thursday, but temperatures will remain hot next weekend as well.

An extreme heat watch was issued for Tuesday morning through at least Friday evening for the all of Los Angeles County, preceded by a heat advisory in effect through 10 a.m. Tuesday.

Temperature reached 97 degrees in downtown Los Angeles on Sunday, and surpassed 100 in many parts of the San Fernando, Santa Clarita and Antelope valleys. Similar numbers were expected to continue for several days, with overnight lows heating up as well, remaining in the 70s in the valleys, according to the National Weather Service.

Orange County was feeling the heat as well, with a heat advisory in effect until at least 10 a.m. Tuesday followed by an extreme heat watch until Friday. Anaheim reached a high of 97 on Sunday and was expected to hit 94, 96, 96 and 98 Monday through Thursday.

While highs in coastal areas will mainly remain below 90 degrees, overnight temperatures will not drop below the lower 70s, which will especially affect those without access to air conditioning.

According to the National Weather Service, there is some cooling expected on Saturday, but in the past these heat waves have held on a little longer than forecast.

"We'll see some cooling on Saturday but some people probably won't notice because it will still be in the upper 90s to low hundreds left of the mountains, and still above 110 in the low deserts. But there is some indication the end of the weekend, early next week that ridge of high pressure is going to get pushed back to the east, so we may see some more noticeable cooling, that's really at the very end of the forecast period so there's still some uncertainty," said Oswant.

In the Inland Empire, temperatures of up to 117 degrees are expected in the Coachella Valley and the San Gorgonio Pass near Banning this week, with overnight temperatures about 5 to 8 degrees above normal, according to the NWS.

"The ridge remains stationary and locked in over the desert southwest, translating to the persistence of high temperatures remaining on an average of 5 to 10 degrees above average throughout the rest of the workweek," the National Weather Service said.

Temperatures in western areas of Riverside County were expected to range from 100 to 107 all week with overnight temperatures in the low to mid 70s.

An extreme heat warning was in effect until at least 8 p.m. Friday for the Coachella Valley and the San Gorgonio Pass near Banning.

An extreme heat watch is also in effect Tuesday morning through Friday evening for the Riverside County mountains and valleys, preceded by a less serious heat advisory for the same areas.

The weather will also produce elevated wildfire danger, with "increased risk for large plume-dominated fire behavior" away from the coast, according to the National Weather Service. No major wind events are expected in the Southland this week.

In San Diego County, a heat advisory is in effect from 10 a.m. Tuesday to 8 p.m. Friday for the coastal areas. A heat advisory is in effect until 10 a.m. Tuesday, then an extreme heat warning is in effect from 10 a.m. Tuesday to 8 p.m. Friday for the mountains and valleys. Plus, an extreme heat warning is in effect until 8 p.m. Friday for the deserts.

Widespread moderate to locally major heat risk is expected for the coast, valleys and mountains except near the beaches and for the higher elevations in the mountains, with major to extreme heat risk for the lower deserts.

Downtown San Diego reached 86 degrees on Sunday, and was expected to climb to 88 by Thursday. In the county's desert area, Borrego Springs reached 112 on Sunday, and could hit 114 by Wednesday, according to the NWS.

Inland highs will range from 95 to 107 degrees this week, with nighttime lows only dropping to the mid-70s. The low deserts are consistently expected to see highs of 110-115 degrees Tuesday through Friday, along with major to extreme heat risk, the National Weather Service said.

Health officials advised people to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun during the hottest parts of the day and check up on relatives and neighbors.

The public was also urged to never leave children or pets in parked vehicles for even a minute, as temperatures inside vehicles can reach deadly levels in virtually no time.

City News Service contributed to this report.