The worst of a record Southern California heat wave still to come. What you need to know

The worst heat wave of the year will continue to broil Southern California at least until Wednesday.

Here is a rundown of what to expect:

The forecast

Saturday and Sunday will see "high" and "very high" heat levels in many areas, said Tom Fisher, a meteorologist with the National Weather Service in Oxnard.

But Sunday will probably bring the heat wave’s most intense temperatures.

Heat warnings have been issued for inland and valley areas — which will see triple-digit temperatures with some places topping 110 degrees — but also some coastal cities where temperatures will reach into the 90s.

"A prolonged period of very hot conditions with minimal coastal clouds is expected as high pressure aloft remains anchored over the West,'' the National Weather Service said. "Triple-digit heat will be common for many valley and mountain locations through early next week. Record-breaking heat will produce a very high risk of heat illness.''

Sweltering temperatures will continue into next week, with some cooling expected by midweek.

Some inland areas have set daily temperature records for the last three days.

Energy grid challenges

The California Independent System Operator, which manages the power grid, has extended a Flex Alert into Saturday, officials announced Friday evening.

During a Flex Alert, consumers are asked to conserve energy from 4 to 9 p.m., hours when the grid is most stressed. Officials have warned rolling blackouts are possible during the heat wave due to excessive demand.

Here is a guide for how to save energy during Flex Alerts.

Here is a guide for how to stay safe during heat waves.

This story originally appeared in Los Angeles Times.