Another Scorcher Wednesday but Cooling Trend Ahead

The heat wave roasting parts of Riverside County this week is expected to peak Wednesday as humidity generated from slow moving storms adds to the already uncomfortable conditions and could possibly lead to flash flooding.

A National Weather Service heat advisory is set to remain in effect until 6 p.m. Thursday in the valleys around Riverside. A flash flood watch for the entire county will also extend through Thursday evening.

Forecasters said high pressure aloft would keep conditions toasty Wednesday with high temperatures in some areas up to 15 degrees above average. The low deserts are expected to remain closer to normal, but muggy.

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Highs of 100 to 105 degrees are forecast Wednesday for the valleys, 88 to 94 degrees in the mountains and 101 to 106 along the San Gorgonio Pass and 103 to 108 degrees in the Coachella Valley.

A chance of afternoon and early evening thunderstorms is also in the forecast. The weather service pegged the chance at measurable precipitation at 20 percent in the Coachella Valley and the valleys around Riverside, 30 percent along the San Gorgonio Pass and 50 percent in the mountains.

Forecasters said the sea breeze and east winds would converge this afternoon, which will allow storms to develop. Locally heavy rainfall and flash flooding could be possible near the storms.

“Light steering winds today will result in slow moving storms and a threat of flash flooding, especially over the mountains, deserts and portions of the Inland Empire,” according to the weather service.

Areas in and below recently burned areas would be particularly susceptible to heavy runoff and debris flows should strong thunderstorms develop nearby.

Forecasters also urged people to protect themselves and their loved ones against dehydration, heat stroke and other heat-related illnesses. Residents were advised to stay well-hydrated, avoid working in the sun, check on neighbors and relatives -- especially the elderly -- and provide plenty of water to pets and livestock.

Cooler weather is expected to spread inland from the coast starting Friday.

• --City News Service, photo via Pixabay