Nacreous Clouds

My last working day before the Christmas break. Storm Pia doesn't seem to making much of an impression in Edinburgh. A bit breezy, but mainly sunny spells. Being the last day before the break, it is a busy morning. Had to go to the bank again, so no lunchtime walk, the straight back in to work to find out the person who raised the ticket hadn't provided all the information required. So i will have to wait until the New Year.

On the after work walk, I spotted nacreous clouds shining bright just after sunset. The clouds mainly occur in polar regions, especially over Antarctica, at an altitude between 15,000m and 24,000m above sea level, in the troposphere, when the air temperature is below -78°C and the sun is between 1° and 6° below the horizon. he clouds are much rarer at lower latitudes, so quite lucky to catch them just before the sun slipped below the 6° limit. These ones will be at a higher altitude than in polar regions, so nearer 24,000m ASL. Extra 1 shows a plane flying below the clouds heading SE. Extra 2 a wide angle shot showing the clouds in context.