The Hailstorm II pairs an advanced liquid cooling system with a blustery current of coldair driven by three front intake fans and a large rear exhaust fan.
The forecasters added that the colder than average conditions had been caused by frequent easterly and northerly winds, bringing coldair to the UK from polar and northern European regions.
The initial "push" upward by the cold front on that balloon filled with surface air is like a child letting a helium-filled balloon go -- it just keeps rising.
It was to help the UK to assess the risk of an attack using biological agents by providing important information about their likely dispersion in the open air during the Cold War.