The average high for the start of January is right around 40°, with the low being about 28°. We can expect high temperatures to slowly decrease toward Sunday, starting off in the mid-50s and ending in the upper-40s. Lows will remain fairly steady in the mid- to upper-30s.
This is thanks to repeated systems impacting the region every 24-36 hours for the next couple days. These systems will bring rain to the west side of the state with heavy mountain snow, but aren’t expected to have enough moisture to bring more than some isolated drizzle to the Columbia Basin. Despite the lack of precipitation, we will see some impacts from these systems. Breezy conditions are expected Saturday, though right now it doesn’t look like we will reach levels strong enough to warrant a wind advisory in the Tri-Cities. I don’t think it will be calm for the rest of the weekend, but Saturday should be the worst day for wind.
I decided to use the mostly cloudy graphics for the forecast at the top of this discussion, but it won’t be mostly cloudy the entire time. This is one of the downsides to having simplified weather graphics, since there’s no decent weather symbol that says “fluctuating between sunny and cloudy.” Clouds will increase each time a weather system approaches the Cascade Mountains, but once it passes east of them, our skies should clear – possibly providing a few hours of cloudlessness. Repeat this through the weekend and that’s the actual forecast.
The biggest thing this pattern will do is make it so that inversions are hard to develop. This makes fog unlikely, which helps our temperatures to remain warm. For an inversion to form in our area, the atmosphere needs to be stable so that cold air can sink to the bottom of the basin. That won’t be happening through the weekend because every front that comes into the Pacific Northwest brings in wind that moves the air around.
If you’re traveling over the mountains this weekend, be sure to check road conditions and keep an emergency kit in your car. Snoqualmie Pass, which is the lowest of the major Cascade Passes, is expecting snow Thursday, Saturday, and Sunday. Friday’s warm front will be warm enough to raise snow levels to around 4,000 feet. This would cause snow to switch to rain on Snoqualmie, but isn’t high enough to make that switch on White or Stevens Pass.
All in all, it looks like we’ll have a halfway decent weekend. That is, halfway decent for the Tri-Cities in January. I’ll have up-to-date weather analysis over on Tri-Cities Weather on Facebook. On top of this, you can now check current radar data by clicking this link to view my new interactive radar map.
