Light Snow Tonight and Tomorrow Morning Over Northwest and Eastern Washington. And Cold Record Fall.

 More snow is coming tonight for the lowlands of Northwest Washington and the Columbia Basin.  

But before I get into that, check out this morning's visible satellite image showing a nearly cloud-free Washington State and northern Oregon.   Just spectacular.  

You can see the snow over the mountains as well as regions of non-mountain snow over the eastern Washington and Oregon lowlands. 

As predicted, this morning was very cold across the region, with several observing stations with temperatures dropping to daily records (see below). Over the lowlands of western Washington and Oregon, many locations dropped into the teens, particularly away from the water.   East of the Cascades, single digits were prevalent, with some locations dropping below 0F.   One location in eastern Oregon declined to -10F!

As noted, daily low-temperature records were broken at several locations, such as Seattle 23° (old record 24° in 2018),  and Olympia 14° (old record 16° in 2018). 

A weak upper-level disturbance, embedded in northwesterly flow aloft, will move through tonight and tomorrow morning.  The result will be light snow.  Below is the forecast by the UW high-resolution model of snowfall through 10 AM tomorrow.  Up to about an inch over Northwest Washington and the Columbia Basin, with even more on the northwest side of the Olympics, forced by northwesterly (from the northwest) airflow moving up the terrain.

With such a wind direction (northwesterly), central and southern Puget Sound is in the rainshadow of the Olympics, and areas on the eastern slopes of the Cascades are in the rainshadow of the Cascades.

I should note that the latest National Weather Service high-resolution model (HRRR) forecast for the same period is similar (see below), but pushes the light snow into north Seattle.

I should note, that such detailed forecasts were not possible twenty years ago.  We have come a long way!

Finally, a major snowfall looks likely in the Cascades and mountains of BC on Sunday into Tuesday.  More later.