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

There will be more snow tonight in the lowlands of Northwest Washington and the Columbia River Basin.

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

You can see snow in the mountains as well as non-mountain snow in the lowlands east of Washington and Oregon.

According to the forecast, it will be very cold this morning across the region, with some monitoring stations having daily record temperatures (see below). On the lowlands of western Washington and Oregon, many sites are open to teenagers, especially away from the water. East of the Cascades, single digits are common, with some positions falling below 0F. One location in eastern Oregon dropped 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) year 2018).

A weak superior disturbance, located in the NW current, will move through tonight and tomorrow morning. There will be light snow as a result. Below is the UW high-resolution model forecast for snowfall until 10 a.m. tomorrow. Up to about an inch over Northwest Washington and the Columbia River Basin, even more northwest of the Olympics, is forced by northwesterly (from the northwest) air currents moving up the terrain.

With such wind direction (towards north), Puget Sound in the center and south is in the rain zone of the Olympics, and areas on the eastern slopes of the Cascades are in the rain zone of the Cascades.

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

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

Finally, a heavy snowfall looks likely in the Cascades and the BC mountains Sunday through Tuesday. More late.