Very strong wind last night into this morning (a look at the mountain wave)

12/19/24 4:30pm: Hi, hope you are having a good Thu. I had a good ski tour this morning, followed by some work this afternoon but I wanted to mention the really strong winds that occurred last night into this morning near the base of the foothills and over the Front Range mountains, especially in the upper parts of Gilpin, northern Jefferson County, Boulder county and Larimer county with some wind-gusts of 80-100mph early this morning near Boulder and Golden (extending to Louisville but not much further east).

We had strong wind in Westminster but nothing out of the ordinary (gusts to 45 mph last night, so that is why I didn't mention it)...but it turns out the mountain wave was breaking just west of us, right near the base of the foothills producing a 102 mph gust just west of Boulder and 97 mph gust near Golden (over upper White Ranch). Other notable wind-gust reports include: 85mph at Dakota Hills (near Black Hawk) and 71 mph in Jefferson (north of Fairplay).

These strong, westerly downslope Chinook winds are common during the winter. I have provided some graphics below (along with some graphics from Den/Bou NWS showing the high wind-gusts reports from last night into this morning).

Here is some pertinent info about mountain wave formation from a post I made in 2022, still very relevant.

"t's all related to the development of a mountain-wave along/east of the Cont. Divide. We typically get very strong Chinook, downslope winds ahead or just after winter-storms during late fall, winter and spring.

A mountain wave forms when there is a very stable layer of air just above the mountain tops. There is typically cold, higher pressure air west of the front-range (central mountains), with comparatively warm, lower pressure air on the plains. A high-amplitude mountain wave forms along the lee-side of the Front Range mountains. Basically the wind is pushed up and over the mountains, it hits the stable layer and then gravity forces the wind to move back down the slopes east of the Cont. Divide: forming a wave of wind.

Then we get further acceleration of the wind due to the terrain near the base of the foothills (near Rocky Flats / Marshall Mesa). Since it's a flat mesa that then drops off several hundred feet east of Broomfield...a micro area of low pressure sets up on the plains (east of Broomfield). The wind is pulled into this micro low to the east...and this can lead to very high wind-gust to wind-speed ratios.

I learned in my mountain climatology class that Rocky Flats area has some of the highest wind-gusts to wind-speed ratios in the world during downslope wind-events due to this terrain feature. Just like last week, not uncommon to see sustained winds around 70 mph but with wind-gusts of 100 to 120 mph on/near Rocky Flats and Marshall Mesa."

The good news is, the wind has already calmed down quite a bit and is expected to remain calm / low wind into Fri am. Then stronger wind, re-develops for the front-range mountains (mostly above 9k ft) after 12pm tomorrow (westerly wind-gusts of 30-50mph).

How were the wind conditions in your neck of the woods last night and today? We had some strong wind up on the ridgelines but not too bad in lower areas.