Potentially record-breaking heat expected to hit Southern California

A heat wave will land full force in Southern California Friday and continue into Saturday, potentially toppling some temperature records before things start to cool off Sunday.

"High pressure will bring very warm and dry weather to interior areas, peaking today and Saturday," according to the National Weather Service. "A few record high temperatures will be possible. Coastal areas will be much cooler with continued night through morning low clouds and fog. A cooling trend will start Sunday but another heat wave is expected by the middle of next week."

The first signs of hot stretch showed up on Thursday, delivering a 100- degree afternoon reading in Acton, along with 97 in Woodland Hills, 96 in Chatsworth and Saugus, 94 in Van Nuys and 91 in Pasadena.

There's more to come Friday and Saturday -- with excessive heat warnings and heat advisories kicking on Friday morning and stretching through Saturday night.

"Given the current trends it looks like everything is on track for an even hotter day Friday across inland areas," according to the NWS.

The NWS predicted temps as high as 107 in the Antelope Valley -- where an excessive heat warning will be in place through 10 p.m. Saturday.

Heat advisories will be in place through 8 p.m. Saturday in the Santa Monica Mountains and San Fernando, San Gabriel and Santa Clarita valleys. Temps could hit 98 in the interior portions of Santa Monica Mountains, and could range between 95 and 102 in the valleys.

A heat advisory will also be in place for the Los Angeles County Mountains through 10 p.m. Saturday, with temperatures up to 100 expected, mainly at lower elevations.

Forecasters initially said the heat wouldn't reach record levels, but on Friday, they indicated that some new marks could be set in interior valleys, mountains and desert areas, with the Antelope Valley the most likely contender. Forecasters noted that Palmdale could top its record for the date of 103.

Another hot day is expected Saturday, though the forecast calls for slightly cooler temps as onshore flow increases.

"With a slight increase in onshore flow on Saturday expect a couple of degrees of cooling in the coastal and nearby valley areas with a repeat of overnight and early morning stratus south of Point Conception while interior areas warm a couple of degrees," according to the NWS.

On Sunday, a deepening marine layer promises to mitigate the heat a bit more, with highs still above normal but only by about 5 degrees or so, according to the NWS. Monday, temperatures are expected to be closer to normal.

As usual during heat waves, forecasters urged people to drink plenty of fluids, seek out air-conditioned spaces and check in on vulnerable relatives and neighbors.

"Extreme heat will significantly increase the potential for heat-related illnesses, particularly for those working or participating in outdoor activities," according to the NWS.

"Young children and pets should never be left unattended in vehicles under any circumstances. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in a matter of minutes."