I have a new podcast that provides an update on the snow forecast for this weekend over the region. There will be huge variations in snow amounts from zero to several feet!
Most of the time, you can not see the air move. You can feel it, but the complex, turbulent motions are invisible to you, except when it interacts with leaves and branches on trees and plants. But for a few weeks of the year, the sky is full of small, cotton-like tuffs that like a natural MRI machine reveals the complex three-dimensional motions of the atmosphere. Cottonwood season. And we right in the middle of it. Being cottonwood aware is of particular value this year. It reveals the active dispersion and movement of air that makes the outdoors essentially COVID safe, and thus should be of some comfort for those nervous about transmission outside. Cottonwood seeds are embedded in small cotton-like fibers. A million seeds weigh about 3 pounds. Yes, each seed and tuff weights about .000003 pounds. And that fact, plus the cottonwood tuff, means that these seeds fall VERY, VERY, VERY slowly. So slowly that they are excellent markers for the three-dimensional flow of the...
My podcast today will both provide the weekend weather forecast and talk about the history of wildfires in the Pacific Northwest. Wildfires and associated smoke are a major concern in the region, and some media, politicians, and others have suggested that wildfires and wildfire smoke are not normal and are a potent sign of a changing climate. They are not correct. Wildfires and their smoke are a natural part of the Northwest ecosystem. What was not normal was the period of suppressed fire during the later portion of the 20th century. A good illustration is the visit of Mark Twain in August 1895, a summer in which the U.S. Weather Bureau noted "the sun was almost entirely obscured by excessive smoke from wildfires." Twain was invited to speak in Olympia, where the chairman of the reception committee apologized for "smoke so dense that you cannot see our mountains and our forests, which are now on fire". Twain retorted “As for the smoke, I do not so much mind, I...
It might seem ironic....the approach of a warm front can produce substantial snow over the lowlands of western Washington and in our mountains. And such an event is predicted to occur later tomorrow, with Northwest Washington particularly vulnerable to both snow and freezing rain. The mountains will also get hit hard with several feet of snow. Today's Situation The freezing level over Puget Sound is now at roughly 1900 ft right (see a plot of temperatures from planes coming in and out of Sea-Tac Airport. The snow level is about 1000 ft below that (snow melts between the freezing and snow levels, below the snow level only rain is observed) Where precipitation is heavy, the snow and freezing levels can descend hundreds of feet as a result of melting snow. A weak system is moving in today, resulting in rain over the lowlands with one exception: around Bellingham where cool flow out of the Fraser River Valley will develop this afternoon and evening. The snowfall prediction from...
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