Weather 12-11-19

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A relatively progressive Pacific weather system has triggered a broad band of snow from the Wenatchee Valley to Spokane. Snow totals will generally range from 1 to 2 with local 2-4 inch amounts over the Mountains. While the threat of precipitation will decrease throughout the morning, plenty of moisture will remain trapped in the boundary layer, which suggest widespread fog and low clouds will persist over many locations into the afternoon. The next storm system is expected to move into Northcentral Washington by late afternoon, so the break between precipitation events will be brief. The next round of precipitation will be warmer than the current one so we expect to see a gradual transition from snow to rain, or just rain for much of the lower Columbia Basin and the Wenatchee Valley, while farther north the event will start as more light snow. There is a 60% chance of rain late this afternoon and a 60% chance of rain mixed with snow tonight, highs today in the mid 30’s.

Weather models continue to show a strong jet moving into Oregon with several waves along and north of the jet bringing rain and snow to the area again on Thursday. Precipitation is expected to fall as valley rain and mountain snow along and south of the I-90 corridor. Clouds and a 60% chance of rain on Thursday but warmer with afternoon high temperatures in the lower 40’s.

For Friday and Saturday, Northcentral Washington will begin to trend to drier and cooler as the upper level jet drops south of Washington steering the moisture outside of the region with it. The weather will become mostly benign as a ridge of high pressure begins to build along the coast and pushes cooler, drier air into the Inland Northwest. Early morning patchy fog over the weekend is the only impactful weather for this period. Under mostly sunny skies, high temperatures on Friday will be in the lower 40’s while Saturday will see highs in the upper 30’s.

Mostly cloudy for Sunday, Monday and Tuesday with a 20% chance of rain mixed with snow showers with afternoon highs in the mid 30’s.