Temperatures are expected to soar into the 90s in Long Beach and elsewhere in the Southern California region, but forecasters say the heat will abate by Saturday and Sunday when thousands are expected to attend the Acura Grand Prix of Long Beach in Downtown.

A heat advisory will be in effect beginning at 11 a.m. Wednesday, and last through 6 p.m. Friday. The National Weather Service forecast calls for highs of 89 degrees on Wednesday, 92 degrees on Thursday and 91 degrees on Friday.

The temperature will dip down to 74 degrees on Saturday and 69 degrees on Sunday, the day of the IndyCar race in Long Beach. Sunny skies are expected through the weekend, according to the NWS forecast.

Weather is often the biggest predictor of crowd size, organizers of the Grand Prix have said. This year 180,000 attendees are expected over the three-day race, April 8-10.

Farther inland, temperatures this week are expected to reach 100 degrees in Santa Clarita, San Gabriel and the San Fernando valleys.

Northerly winds are expected to reach between 25 mph and 40 mph with damaging gusts up to 65 mph in the Los Angeles County mountains, excluding the Santa Monica Mountain range.

Travel will be difficult, especially for high-profile vehicles, the National Weather Service says.