Most of the area will be dry to start Saturday with a little bit of sun. High clouds move in pretty quickly ahead of a stronger weather system.
This will bring increasing rain and mountain snow from Saturday evening through the day on Sunday, only tapering off on Sunday evening. Expect very poor pass travel, and folks headed to the Apple Cup should be aware that getting back from Pullman on Saturday night or all day Sunday could be very difficult indeed.
Expect 8 to 18 inches of snowfall in the passes from Saturday night through Sunday night with isolated higher totals. In the lowlands, more than a half-inch of rain will fall and breezes could top 30 mph on Sunday.
Colder air arrives on Sunday evening as precipitation comes to an end, but snow levels will fall below 1,000 feet, meaning we could have some foothills or higher hills snowflakes into Sunday night and early Monday morning. I don’t expect any significant difficulty with travel in the lowlands heading into Monday morning, however.
Monday itself will be mainly dry with some sun and highs in the 40s. It now looks like we will get through most of Tuesday without precipitation but temperatures will be quite chilly with lows below freezing and highs Tuesday near 40.
Chance of lowland snow
Precipitation looks to arrive Tuesday night through Wednesday with a trough of low pressure aloft falling south out of western British Columbia. Just how much moisture is available with this system is unclear but it will be cold enough for some lowland snow, particularly above about 200 to 300 feet elevation from Tuesday night through Wednesday.
We’ll be updating that forecast as we get closer, but early outlooks have some light accumulations during this time frame in lowland locations.
There are signs of even colder air plunging into the region around next Thursday and Friday, possibly lasting several days. If this pans out — and it is not a certainty — high temperatures may barely get above freezing some days with nights well below freezing.
It will be something to keep an eye out for as it would be the coldest air of the season so far — if it occurs. If it does get that cold, however, it could well be too dry for precipitation.
Again, the details will come into better focus in the coming days and the longer-range forecast is subject to possibly substantial changes, so stay tuned.
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