Although the big local weather story this week has been the heavy rain and serious flooding over the Pacific Northwest, there WAS another extreme weather feature: powerful downslope winds on Wednesday that caused massive tree damage and power outages over the eastern slopes of the Cascades.
Some of the winds exceeded 100 mph from the west.
Leavenworth, on the eastern slopes of the Washington Cascades, was hit particularly hard, with the entire town losing power, forcing the cancellation of the Christmas Lights festival. Here are a few samples of the destruction:
The winds at Mission Ridge (6730 ft) are shown below (the dark blue line indicates the sustained wind, the top of the light blue area indicates the gusts, the bottom of the light blue indicates the low winds during the hour).
Very windy from early Wednesday through early Thursday, with many gusts over 100 mph. And the winds were exceedingly gusty.
Were these winds predicted ahead of time? You bet they were. Below is the forecast surface winds from the UW WRF modeling system for 1 PM Wednesday.
Reds are over 70 knots (81 mph). You can see bands of localized strong winds on the eastern side of the Cascades.
The NOAA high-resolution model (HRRR, High Resolution Rapid Refresh) was doing the same thing, as shown by the forecast wind gusts at 7 PM Wednesday.
So why such localized winds?
We live in Leavenworth. It was not just the strong winds, it was a long lasting event that started about 2PM and continued past midnight. It didn't help that the soil was saturated by heavy rain, making trees more vulnerable to falling. The worst winds were in city limits. My impression is that the strongest winds were funneled through the Tumwater Canyon, which opens up right at the entrance of town. A few miles to the South, in the area where the Icicle River merges with the Wenatchee River, winds were not nearly as strong. They had their own problems to deal with as that is where a lot of the flooding was.
ReplyDeleteI have been seeing some weather sites mentioning strong wind coming in on Monday and Tuesday night. Have you seen anything about this?
ReplyDeleteThe Weather Channel has been predicting a significant wind event on Monday in the Puget Sound for a couple of days. Their prediction now extends to Tuesday. But the local news channels aren't reporting on it. King 5 says Monday will be gusty, but no mention of wind on Tuesday. Pacific Northwest Weather Watch on youtube is predicting a significant wind event in the Puget Sound area on Monday. It would be helpful to get Cliff's take. How can so many weather "experts" differ so widely about weather only two days in the future?
DeleteThanks Cliff Mass for all your hard work updating us and educating us! :) I have learned a lot and enjoy reading all your predictions!
DeleteCliff,
ReplyDeleteWe have all of the components for an historic snow event beginning on or about the 22nd or 23rd. It's literally Goldilocks.
Any thoughts on that?
Still too far out to consider, but the forecast is concerning (or joyful) depending on your preference for snow and cold. Once we are out only 7 days or less, forecast skill jumps considerably. Could be interesting for sure.
DeleteWhat I also found surprising was that when I got home to Leavenworth at 530pm, it was 70 degrees, and was still 68 when I went to bed at 930pm. A powerful chinook!
ReplyDeleteDo you think it is possible this is related to Climate Change or just a natural fluke of weather?
ReplyDeleteI believe this is normal as we get events much like this most years during this time (Nov through mid Jan at minimum) and some years are worse (like this year).
DeleteComment - the weather stations mentioned above Lake Wenatchee, at Mission Ridge and above Leavenworth are Northwest Avalanche Center / WSDOT / ski area network.
ReplyDeleteI live in Prosser, we indeed got some strong winds, what was impressive was how long the event lasted, nearly 24 hours from early Wednesday morning until well into the night.
ReplyDeleteWe occasionally get strong winds here, is it safe to say that it is always correlated with weather events on the West side of the mountains?
I was trying to find the wind speed data you showed on the UW WRF site but couldn't find it when going to "past runs" here: https://a.atmos.washington.edu/wrfrt/rt/otherdates.html. Can you provide a link to the data? I'd like to then see what the predictions are for Monday-Wednesday of this week. Thanks!
ReplyDeleteThe storm in Leavenworth was scary and destructive. Folks do read your blog over here, and I'm sure many would love it if you included forecasting for this area- for our valley and the passes (which are our life blood). Even if it is just to tell us today how to prepare for this week. Where could we find daily expected rain and snow totals for here and the passes? And (gulp) what kind of wind event is expected Wednesday?
ReplyDelete