Anthelion theWeather Club Fri, 06/10/2017 - 13:57

A faint, curved halo―sometimes called a mock sun―that appears opposite to, and at the same elevation as, the real sun. It is a rare phenomenon, the cause of which remains hotly debated.

Anticyclone theWeather Club Wed, 23/08/2017 - 11:29

A weather system with higher pressure in the centre than in its surroundings. An anticyclone is characterised on a weather chart by completely closed isobars, roughly circular in form, spreading out from the central high pressure area. The presence of an anticyclone system usually results in fine, cloudless weather.

Altostratus (As) theWeather Club Mon, 24/07/2017 - 14:42

One of the 10 characteristic cloud types (or cloud genera) recognised by the International Cloud Atlas. Its name comes from altum (height) and stratus (spread out). It appears as a greyish or bluish sheet of cloud, partly or totally covering the sky, but with parts sufficiently thin to at least vaguely reveal the sun.