A storm system that battered the southwestern U.S. earlier this week is sending waves of moisture northward today, and is triggering rain as far north as Spokane and westward into parts of the normally dry Columbia Basin.
In Spokane, rain has been falling steadily since about 8 a.m.
By 2 p.m. Felts Field had seen a quarter inch of rain while Spokane International Airport gathered 0.15 inches. Deer Park was also feeling the brunt of the storm at .22 inches. Lind in Adams County saw .40 inches.
A persistent deformation band had formed this morning in the upper atmosphere, allowing moisture from the south to condense from an upward momentum. The band was the result of streams of high-altitude air moving in different directions - a clockwise flow left over from Wednesday’s fair weather versus a counter-clockwise flow at the leading edge of the storm.
Beneath the band, the rising moisture easily condenses to rain.
Similar weather features brought heavy rains at the end of last spring.
In North Idaho, the chances of rain showers were pegged at 80 percent this afternoon.
Today’s wet weather is just a taste of what forecasters expect as the weekend arrives.
A short shot of higher air pressure on Friday is expected to bring partly sunny skies in Spokane and Coeur d’Alene with high temperatures reaching a pleasant 63 to 65 degrees.
More rain arrives by Saturday as a new weather system off the Pacific Ocean swings into the coast, initially bringing mild, wet conditions in advance of a cold front on Sunday.
Forecasters said the chance of rain goes from 60 percent on Saturday and Saturday night with a tenth to quarter inch possible. The chance of rain rises to 90 percent on Sunday, but forecasters have not given a predicted rainfall amount for Sunday.
Coeur d’Alene has a 100 percent chance of rain on Sunday, an indication that computer forecast models are showing heavy moisture arriving with the Pacific system.
The Cascades could see the heaviest rain with 2 to 4 inches possible, and that’s enough to raise the levels of small streams dramatically.
The cold front arriving later Sunday could set the stage for the region’s first frost of the season on Monday night, and bring snow showers to the upper slopes of the region’s mountains.
At 7 a.m., it was a mild 54 at Spokane International Airport. The temperature remained at 54 at 2 p.m.