A winter storm watch was upgraded to a winter storm warning this afternoon for far Eastern Washington and North Idaho as well as locations closer to the Cascades as an arctic weather system approached the region with a potential for heavy snow.
A winter weather advisory for lesser amounts of snow was in effect for other parts of the region, including the Columbia Basin.
The warning comes after the low temperature dropped to minus-5 degrees in Spokane early today, but by afternoon the temperature across the Spokane and Coeur d’Alene area rebounded to anywhere from about 7 to 13 degrees.
At Spokane International Airport at 2:50 p.m., the temperature was 7; at Felts Field, 10; Otis Orchards, 13; and the Veterans Memorial Bridge on Interstate 90 east of Coeur d’Alene, 12.
The National Weather Service issued the warning for Spokane, Stevens, Pend Oreille, Whitman and the northeast corner of Lincoln County in Eastern Washington along with nearly all of North Idaho. In addition, the southeast corner of Washington from the Walla Walla Valley eastward was part of the warning area.
The warning extended as far east as Glacier National Park in Montana.
The storm watch for Wednesday and Thursday called for 4 to 7 inches of snow in valley areas and from 8 to 14 inches in the mountains.
John Livingston, chief meteorologist for the National Weather Service in Spokane, said that like last weekend’s storm, gauging the amount of snow is difficult for forecasters. He said Spokane could see from 2 to 6 inches.
The storm last weekend brought heavier snow amounts to some regions such as Wenatchee, Waterville, Pullman and northern Pend Oreille County while the Spokane and Coeur d’Alene areas saw lighter accumulations.
Temperatures were not expected to be as cold tonight. Lows should be about 2 degrees in Spokane and 5 degrees in Coeur d’Alene with highs in the teens on Wednesday in advance of the predicted snowfall.
A low pressure system originating over the Arctic Ocean was being driven southward today beneath northerly winds in the upper atmosphere that were associated with the outbreak of arctic conditions earlier this week. The storm was predicted to move along the British Columbia coast, and in the process, draw in enough ocean moisture to cause moderate to heavy snowfall amounts. However, the snow by Wednesday night should be a “dry” variety with lower moisture content, making it easier to shovel and maneuver across.
A winter storm watch is issued 24 to 36 hours in advance of a storm and then can be upgraded to a winter storm warning as the predicted arrival moves within 24 hours. Both are for a chance of heavy snow or ice.
Another reinforcing shot of arctic air is expected by Friday with lows dropping below zero on Friday and Saturday nights before rebounding slightly on Sunday. Highs on Saturday are forecast at 3 to 6 degrees.