One more day of a strong inversion and stagnant weather today before an incoming storm system drifts north into the forecast area. Today, more of the same with a low cloud deck, calm wind and cold temperatures with highs later today only in the upper 20’s. By Wednesday, more noticeable weather changes will come our way with mostly cloudy skies during the day and highs in the mid 30’s. An upper level low-pressure system will move in off the Eastern Pacific and break down the ridge of high pressure currently in place. Multiple waves of energy will push across with this low-pressure system with a stronger wave coming overnight Wednesday. Precipitation type will be tricky across the basin and into the Spokane Area and adjacent mountain valley locations. A light glazing of ice may result in slick travel for the Thursday morning commute, including I-90 and Highway 2 across the basin. Valley areas in the east slopes of the northern Cascades and further north across the Okanogan Highlands to the Northern Idaho Panhandle should be cold enough for moisture type to fall predominantly as snow. Snow accumulations for these valleys look to run between 1 to 3 inches. Winter Weather Advisories may be needed for this event due to mixed precipitation and light to moderate snow accumulations.
In the Wenatchee Valley, there is an 80% chance of snow after 10:00 p.m. with 1-2 inches of accumulation expected overnight and a 90% chance of snow and rain on Thursday. Afternoon high temperatures will also warm up Thursday with highs in the upper 30’s. The low will move inland into the Northwest on Friday. This will result in additional energy producing a mixed bag of moisture, including more pockets of freezing rain.
We have a 40% chance of precipitation Friday with highs near 40 degrees. For the weekend Saturday and Sunday, mostly cloudy skies as a weak river of moisture is directed at the northwest bring a 40% chance of rain Saturday and a 30% chance on Sunday, high temperatures in the upper 30’s and lower 40’s.