The flip-flop weather this winter is going to flip back to mild and wet this evening, but not before one or two inches of snow accumulate in the Spokane and Coeur d’Alene areas.
Arctic air that hit the region Wednesday was expected to linger through the day today, but it is going to be scoured out by a new Pacific storm system tonight that is forecast to bring a 60 to 70 percent chance of snow. The snow should change to rain after 10 a.m. Saturday.
Highs today should reach the upper 20s, but Saturday should be milder, with highs moving to the upper 30s and lower 40s over the weekend. The mild weather and rain should continue next week.
It will be the third time since early December that the region has seen a dramatic switch from winter-like cold to milder Pacific air that has melted the intervening snowfalls.
An exaggerated north-south orientation of the upper-level jet stream winds over the past month or more has been responsible for see-saw weather across the globe.
An El Niño warming in the tropical Pacific Ocean is also part of the picture, creating a strong high-pressure ridge along the coast and Western states. The result has been cold air when the ridge moves west and warm air when the ridge shifts east.
Consistent with El Niño, the lower elevations have seen about half the normal amount of snow so far this winter.
Spokane International Airport has had 11.7 inches of snow this season compared with a normal of 24 inches through Jan. 6. At the same time, precipitation has been close to normal, allowing the mountains to gather healthy amounts of snow.
The back-and-forth nature of the weather also has left the region with near-normal average temperatures over the past couple of months.
The coldest weather so far this season came from Dec. 7 through 12, with the coldest reading of 1 degree on Dec. 8 at the airport. It was followed by an inch of rain on Dec. 19 through 21.
A more modest push of arctic air was felt around Christmas, followed by two inches of snow and then three-quarters of an inch of rain from New Year’s Eve through Tuesday.
The cold this week prompted activation of warming centers at the House of Charity and Salvation Army in Spokane and St. Vincent de Paul, 117 E. Walnut, in Coeur d’Alene.