Long-Duration Heat Wave, With Temps Over 100, Expected To Bake Inland Empire Well Into October

SAN BERNARDINO COUNTY, CA — While the calendar indicates fall has arrived, summer-like heat will persist across the Inland Empire this week, with temperatures pushing well into the triple digits as a long-duration heat wave takes hold through the weekend and likely through the following weekend, meteorologists said Tuesday.

According to the National Weather Service, the Riverside metropolitan area and neighboring areas are experiencing brief seasonal relief before a high-pressure ridge strengthens, bringing unseasonably hot conditions from Thursday into next week.

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"A long-duration heat wave, especially for the coast and valleys, is likely to persist for much of next week into the following weekend," according to the NWS.

In the near-term, low-pressure troughs linked to Tropical Storm Odalys and Hurricane Polo near the Baja California peninsula will continue to influence regional weather through Wednesday, keeping temperatures down in the Inland Empire, forecasters said.

But by Thursday, high pressure moving in from the Great Basin of Nevada and Utah will begin dominating weather patterns, ratcheting up temperatures across Southern California.

"High temperatures for the weekend will range from around 5 degrees above average for the lower deserts to as much as 15 to 20 degrees above average for coastal areas into the western valleys," the Weather Service said in its Tuesday forecast discussion.

For the Inland Empire, high temperatures in the Riverside area will top out in the low 90s Tuesday and Wednesday before steadily climbing. Peak daytime highs are projected to reach between 98 and 105 degrees Friday through Sunday, creating widespread moderate to major HeatRisk conditions, forecasters warned.

Overnight lows will offer little relief, remaining in the low 70s through the weekend, potentially tying or breaking daily record-high minimum temperatures for valley locations.

In the Coachella Valley, daytime highs will linger in the low 90s Tuesday before hitting 100 degrees Wednesday and pushing into the 100-to-105-degree range through the weekend, with overnight lows in the mid-70s.

Along with the heat, periods of weak easterly offshore winds are expected over the weekend along coastal mountain slopes and inland valleys, with gusts reaching 25 to 35 mph.

Weather Service forecasters advised residents to take precautions against heat-related illnesses by staying hydrated, limiting strenuous outdoor activity during peak afternoon hours, and checking on vulnerable neighbors and pets.

—City News Service contributed to this report.