Cloud formation over Stromness Harbour

[Dave C]

My brother sent me this unusual cloud formation image from tonight and asked if I knew what it was. I didn't. Can anyone help?

[Paul Knightley]

Looks like a lenticular cloud to me, lit up by the low sun angle…great pic!

[Len W]

Yes, a cloud formed in the crest of a wave, looks like two moist layers to me.

The wave motion presumably initiated by flow over high ground to the south of Stromness?

Len

Wembury

[jack.h...@gmail.com]

I'm sure that was weak mountain wave.  Orkney Mainland is flat but Hoy to the south of Stromness has the 479 metre Ward Hill.  I have an annual holiday in Orkney and stay near Stromness.  I haven't actually seen any evidence of mountain wave but that means nothing.

Today Ben Wyvis (northwest of Inverness) was triggering very weak wave (wind was extremely light) and this photo (from Cawdor) shows the mountain and the feeble wave cloud.

Often the trigger hill (it can be quite low) is not all that obvous - but today was just about apparent.

My wind direction isn't entirely accúrate on thje graphic.  It was blowing basically left to right but with a component towards the camera. 

Jack