The National Weather Service issued the warning as hot conditions through Monday night. Weather official predict highs in the 90 to 100 degree range in the Willamette Valley, Colombia River Gorge, Cascade and Coastal ranges and the foothills.
With the high temperatures comes a high risk of heat stroke, especially for young children and the elderly. the weather service asks people to keep cool during the afternoon and evening, as those hours are typically the hottest of the day. | Current Weather Forecast
KATU meteorologist Mary Loos said the sudden spike in temperatures is caused by "an upper-level low that's going to (draw) some of that warm air up into the area."
Loos said the upper-level low pressure system is expected to come inland off the Northern California coastline Sunday night, triggering thunderstorms for Central Oregon over the next few days.
The storms prompted weather officials to issue a red flag warning for Southern and Central Oregon, with thunderstorms slated to last until at least Tuesday night.
The National Weather Service said the dry fuels across the region could set the stage for numerous fire starts that have the potential to overwhelm initial attack resources.
A red flag warning means that critical fire weather conditions are either occurring now, or will shortly. A combination of strong winds, low relative humidity, and warm temperatures will create explosive fire growth potential.