Last Night's Squall Line

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Last night, between roughly 12:00 and 1:00 AM (depending on where you were) an intense line of thunderstorms and strong winds moved across the Washington coast and swept across western Washington. Winds gusted to 60-70 mph along the coast and to 40-50 mph in places across the interior. A significant number of trees were toppled plus innumerable loss of branches, resulting in power outages affecting thousands of people. Thousands are still without power Tuesday evening. And there was quite a bit of lightning too.

The cause a line of thunderstorms associated with a strong cold front. Here is the radar image at around 12:30 AM (and a close in shot as well). The strongest rain associated with the line is indicated by red color (very, very heavy rain is associated with reds!)

There was a considerable change in virtually all weather parameters with this front. Here are the observations at the top of the atmospheric sciences building here at the UW (click to expand). The winds gusted to 40 mph (top line), the wind direction shifted abruptly to the south, temperature plunged by 6F, pressure spiked upwards (fifth line), and lots of precipitation fell. My dog was terrified.

Was this predicted? Not really. We knew a strong front with good rain was coming in, but did not foresee such an intense event. But with a coastal radar we probably would have seen it coming and been able to provide a few hours warning.

The number of tree losses was undoubtedly aided by the saturated soil. Wet soil has less adhesion to roots...less holding power...making it easier to wind to do its dirty work.

The weather should calm down a bit now, with the jet stream and most of the action going into California, for the next few days. there was an F2 tornado at Aumsville, 10 miles NE of Salem, Oregon.
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