A period of westerly tropospheric flows in Scandinavia is continuing to provide occasions of Mother-of-pearl (MoP) clouds to Finnish observers. Several MoP displays have been observed just before the Christmas at different locations, in particular in Central and Northern parts of Finland, but also at the Southern coast. The photograph taken by Mauri Laitinen in Kuopio, Eastern Finland, shows the beautifully coloured details of the afternoon display of 23rd December.MoP clouds are seen a number of times each winter in Finland, but displays as bright as this one are fairly rare.
Usually the MoP clouds are related to stratospheric temperature colder than -80°C.
