Clouds from what forecasters are calling a monsoonal flow are making their way northward today and could bring the threat of thunderstorms today and Wednesday.
The moisture may also increase humidity in the air, making the late July heat feel even warmer.
Highs today should reach about 90 at Spokane International Airport and several degrees warmer than that in downtown Spokane.
Coeur d’Alene should see 91 and Spokane Valley, 92.
Hot weather is expected to continue through the weekend with highs in the lower to middle 90s on Wednesday through Sunday.
A second round of isolated showers and thunderstorms is possible over the weekend, forecasters said.
The current thunderstorm threat is coming from a southwesterly circulation around a large upper-elevation high pressure area anchored over the Rockies.
A weak low pressure area on the western edge of the mountain high is circulating moisture and storm potential northeastward from Oregon and the California coast.
National Weather Service forecasters said they expect a series of storm impulses to ride along the boundary between the mountain high and the coastal low.
The fetch of moisture in the middle elevation of the atmosphere reaches southward to the ocean waters off southern California.
Thunderstorms are likely to be concentrated along the Idaho-Washington border and confined to areas east of Colville and Ritzville.
Forecasters said there is a potential for heavy rain coming from storms on Wednesday. The Spokane area has a 20 percent chance of thunderstorms today and a 30 percent chance on Wednesday.
Coeur d’Alene has a 40 percent chance of thunderstorms today dropping to 20 percent tonight before rebounding to a 40 percent chance on Wednesday and Wednesday night.
Monday’s high of 95 at Spokane International Airport was the hottest day of the year so far at the area’s official weather reporting station.
At 7 a.m., it was balmy in the region. The Spokane airport and Felts Field were 67 degrees and Coeur d’Alene was 66.
Walla Walla was 77 and had light rain. Pullman was 68.