Robert G. Fovall

Expand your understanding of how air moves by taking a three-dimensional view of atmospheric circulation. Discover what happens when winds change direction and what conditions cause these changes in wind shear.

Scientists have learned a lot about how weather works and have developed sophisticated tools to predict what may happen in our weather. You learn about the sophisticated numerical models these experts use, as well as the inevitable limitations of those models.

In this episode, you encounter some of the most dramatic air-flow patterns found in nature: the swift, turning winds of the cyclone. Trace the lifecycle of the extratropical cyclone, which draws its power from the huge energy generated when different air masses meet.

From thunderstorms to typhoons to driving winds, the world's weather is often tumultuous, destructive, and surprising. And yet, all these phenomena represent Nature's attempt to mitigate extreme conditions. In this introduction, begin to explore some of these extremes as you examine the great complexity of the world weather system.

One of the most familiar and beautiful features of weather is the cloud. In this episode, examine different kinds of clouds, learn how clouds are born, why and how they take their distinctive shapes, and what kinds of conditions are likely to produce clouds.

Add a new element to your understanding of the atmosphere—water—and learn some basic facts about air's capacity to hold water vapor, including the impact of temperature on atmospheric moisture and the implications for weather.

Delve deeper into tumultuous weather as you learn about the formation of towering supercell storms. You also take a detailed look at how the conditions that produce these storms can lead to deadly tornadoes.

Shift your eyes to the sky and examine what happens in a higher level of the atmosphere called the middle troposphere. With this examination, you discover two new features in large weather systems—troughs and ridges that occur in areas of very low and very high pressure—and see how these features affect the weather.

What is air made of? Is it always true that hot air rises and cold air sinks? Learn more about the air that surrounds us and cushions us from the outer reaches of space, and examine the various layers that make up the earth's atmosphere.

Energy radiates all around us, streaming in from sunbeams and emanating from every object on Earth. Investigate the various kinds of radiation represented on the electromagnetic spectrum, and see how these forms of energy—assisted by the greenhouse effect—make life possible on our planet.