[BAA-ebulletin 00903] Nacreous clouds - again!

[BAA electronic bulletins service]

The upper atmospheric conditions that gave rise to the display of stratospheric 
clouds at the beginning of February look set to return at the end of the month. 
Last time whilst some of the clouds showed the "nacreous" or "mother-of-pearl" 
forms, the majority appeared like thin stratocumulus, a normal form of quiet 
weather cloud.  The difference however was that the stratospheric clouds 
remained relatively bright long after normal stratocumulus would have turned 
dark at sunset.  The clouds might be seen from northern Scotland from February 
27, and later from southern England until perhaps March 1.  The current 
forecast weather conditions favour Scotland seeing the clouds before sunrise on 
February 28, with southern England seeing them after sunset the same day.  The 
rest of the time it may be too cloudy with lower level clouds.

There are plenty of pictures of the clouds on the web, eg 
http://www.bbc.co.uk/news/in-pictures-35462395 though virtually all these show 
the spectacularly coloured form, rather than the generally colourless diffuse 
form.

Jonathan Shanklin
BAS Fellow
British Antarctic Survey, Madingley Road, Cambridge CB3 0ET, England