Weather system bringing rain, snow to Spokane region

The cool beginning to fall for the Spokane region is about to get cooler with a band of rainstorms that likely will hit Friday and continue into early next week.

The systems rolling in from the Cascades are expected to dump measurable snow amounts on some highway passes and Eastern Washington mountains, said Rachel Fewkes, a meteorologist with the National Weather Service in Spokane.

“We have a couple of different waves coming in that are going to bring some cooler temperatures, breezy winds and widespread precipitation across the region,” Fewkes said. “It’s going to usher in a lot of moisture.”

The weather event, fueled by a deep low-pressure system spinning ashore on the Pacific Coast, could bring between a 1/2 inch and 3/4 inches of rain in lower areas around Spokane and 1 to 2 inches of rain in North Idaho and northeastern Washington.

“Some of that will fall as snow,” Fewkes said.

While the storms will start with rain on Friday, the snow levels will gradually fall from between 5,000 to 4,000 feet on Saturday and then from 4,000 to 3,000 feet on Sunday.

“Stevens Pass will be the hardest hit with between 12 to 16 inches of snow in the forecast,” she said. “Washington Pass (on state Route 20) will be another one that gets snow. They are looking at 10 to 12 inches. Lookout Pass is looking at about 7 to 11 inches.”

The storm also will bring colder weather with highs and lows not changing much.

“Friday is going to be the last warmish day with highs ranging in the low 60s in Spokane to the upper 60s in Lewiston,” she said. “Things will cool down Saturday with highs in the mid-50s. The highs on Sunday, Monday and Tuesday will be in the upper 40s for much of the region.”

The low temperatures will start in the mid-40s through the weekend. “Then, they’ll drop into the low to upper 30s. Monday night into Tuesday is expected to be the coldest night with widespread lows in the 20s, except for the Lewiston area.”

In addition to precipitation, the storms are predicted to generate winds with gusts as fast as 35 mph in the Columbia River Basin near Moses Lake.

“In the Spokane region and further east, we’ll see gusts ranging from 20 to 30 mph,” she said.

Recent rains already have given the region a boost based on seasonal averages, Fewkes said.

So far, as measured at the airport, the Spokane area has received 1.58 inches of rain since the water year began on Oct. 1. The average for this time of year is 0.85 inches.

“So we are close to double our normal since the beginning of October,” she said.

As for the long-term forecast, the region should continue to receive storms indicative of a La Niña weather pattern.

La Niña years are marked by cooling ocean temperatures in the tropical Pacific Ocean that often lead to cooler, wetter winters in the Pacific Northwest, Fewkes said.

“We are currently in a La Niña pattern that is favored to persist through the December-to-February period. After that, it looks like it will transition into neutral conditions,” she said. “So, it will be a short-lived La Niña.”