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The two large movements of "Heavy Weather" describe two different meteorological phenomena that can cause much destruction and discomfort to humans - a heat wave and a supercell. The first movement, "Heat Wave" describes a high pressure system that slowly builds over a large area of the countryside. As the high pressure system strengthens, warm air (which has the natural tendency to rise)is trapped close to ground level. As the high pressure stalls, the mass of warm air builds, and the temperature on the ground soars to unbearable levels. Whereas a heat wave is a result of an overly stable atmosphere, a supercell is a product of a highly unstable atmosphere. When a cold dry air mass collides with a warm moist air mass, powerful and long-lived thunderstorms, called supercells, can form.As the thunderheads build darker and higher, an upwardly rotating column of air, the "updraft," forms. The updraft is responsible for the formation of hail and tornados. As the storm grows more and more powerful, it becomes clear that, while man may be able to control much about his environment, the weather remains out of our grasp. The piece ends as it began as the storm slowly dissipates. Tenuous stability returns to the atmosphere...for now.
--Jess Langston Turner