Blue Skies and Polar Stratospherics.
26th December 2023
It was a lovely blue sky day at Creag Meagaidh today. Although some cloud hung the top of Coire Ardair all day, the rest of the hill enjoyed some nice wintery sunshine through most of the day. There was a relatively uniform layer of fresh snow at all levels. It was only at higher exposed locations was there any evidence of drifting.
All change tomorrow through with strong winds and heavy snow expected. Although the temperature if forecast to rise a bit, it will likely stay below freezing on the tops. After a bit of a false start a couple of weeks ago, looks like winter is properly arriving tomorrow. Expect some wild and serious conditions if out and about tomorrow, I am certainly not expecting much of a view.
The view into Coire Ardair. It was a lovely day to be out, but the fresh snow made for hard going in most places.
Tracks in the snow. I was not the first one up that way.
Driving in to Creag Meagaidh early under clear skies this morning I was hoping I might see some Polar Stratospheric clouds. Recently these rare clouds have been spotted a number of times. They form very high in the atmosphere, at an altitude of between around 15,000m and 25,000m (as the name suggests this is within the Stratosphere). They also only form at very low temperatures, below about −78 °C. These temperatures tend to only occur above the polar regions, hence (as the name suggests) these clouds are usually only seen in the polar regions. However, recently the stratosphere above the UK has been very cold, hence conditions good for these clouds to form.
Polar Stratospheric clouds over Aviemore the other day. Not a great photo, I only had the camera on my phone one me at the time. Also known as mother of pearl clouds due to their iridescence. Unfortunately the colours don’t really come out in this picture.
Fortunately, here is one that I took earlier. Polar Stratospheric clouds I took a few years ago with a better camera which really brings out the iridescence colours.
The temperature of the stratosphere (at a pressure of 10 hPa) for midnight last night. It is unusually cold above the UK at the moment (down to almost −80 °C) , cold enough for the formation of Polar Stratospheric clouds.
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Daniel J Arnold
26th December 2023 10:01 pm
Thanks for breaking trail down slope for us- we spotted you from the summit of Carn Liath and followed your route back down to the glen- great day to be out!
meagaidhadmin
27th December 2023 5:10 pm
No problem, going down was a lot easier than going up had been. As you say it was a lovely day, hope we get a few more of those.