Storm clouds follow a pattern. If you know one of the patterns, you can predict a storm days in advance.
The storm pattern I am about to describe happens between 30° to 60° north latitude which would include North America and Europe and parts of Asia and from 30° to 60° south latitude.
The clouds generally increase in number, size and density as rain draws near. This change in the clouds, is a show that plays out in the blue sky above us.
Stage One – A few wispy cirrus clouds appear in the western sky. Cirrus clouds are thin, high latitude clouds that look like thin strands of cotton candy. They whirl and curl in the sky. (higher than 35,000 feet)
Stage Two – The cirrus clouds thicken and bunch together and become lower in the sky. The cirrus clouds become cirrostratus clouds, layers of cirrus clouds that don’t have a definite top or bottom, but spread out over a large area. (20,000 feet altitude)
Stage Three – The cirrostratus clouds are hidden or replaced by altostratus clouds which are flat, gray clouds that lie in stripes or ridges across the sky. These clouds are dark and lower in the sky. (8,000 feet altitude)
Stage Four – Nimbostratus clouds move in. These clouds are low, dark, thick and shapeless. Their ragged edges produce steady, heavy rain or snow. (about 6,000 feet)
Stage Five – Cumulonimbus clouds, massive and with broad bases may form in the spring and summer. These are the powerful “thunder clouds” which bring hail, lightning and thunder. Heavy rain may pour down to the ground below. (base about 3,000 feet towering up to 16,000 and even up to 65,000 feet high)
As the storm passes the sky may stay overcast with gray stratocumulus clouds. Once these clouds pass through fair weather returns.