Pillows in the Sky: Or maybe much more…

Some clouds may not look very interesting. They are small and often associated with fair weather. Unlike the spectacular cumulonimbus (thunderstorm), small clouds do not stand out. But not so fast, small clouds are all part of the weather picture. Just like the big guys they have an important role to play.

The clouds in the photo to the left are the first signs something is happening. These clouds are plain cumulus. If you use your imagination, they may look like pillows; some could be fluffed up a little while others are just right. On a fair-weather day these clouds may not grow much larger. On other days these clouds could grow into a thunderstorm. Big things start in small packages.

Our weather uses many processes to control global temperatures. Clouds shield the Earth from sunlight during the day, keeping us cooler. Clouds help the Earth retain heat at night, keeping us warmer. When clouds form, heat of condensation is released into the atmosphere. The heat comes from the air that evaporates the water in the first place, from a local pond to hundreds or thousands of miles away. That is how heat is transported from one place to another without changing the temperature of the air along the way. It is called latent heat. The latent heat is released back into the air, warming the air slightly, when the water vapor condenses into back into water droplets or ice crystals.

The small clouds below may not look like much, but they are part of the Earth’s thermostat. And since water covers about 75% of the Earth it is the controlling factor in Earth’s global temperature control.

Photo copyright by Craig Johnson, Weather Briefing, LC., at Cedar Falls, IA