[--MAIN HOME--] [--ALL HABYHINTS--] [--FACEBOOK PAGE--] CLOUD DEVELOPMENT AND EXISTENCE ALOFT METEOROLOGIST JEFF HABY Clouds need two ingredients to develop which are moisture and rising air that is able to saturate the air. Saturated air has a relative humidity of 100%. When this saturated air is cooled additionally, moisture will condense out of the air since the amount of moisture the air can contain decreases as temperature decreases. Lifting the air is a process that will cause the air to cool. Thus, in a region of cloud, the dominate direction of movement will be upward. If the movement is quick and convective, then clouds such of cumulus will be seen. If the movement is slow and dynamic, then clouds such as stratus and cirrus will be seen. Clouds will continue to exist as long as the air is saturated and rising. If the air sinks, then the cloud will begin to dissipate. This is because sinking air warms and thus causes the relative humidity to decrease below 100%. This enhances evaporation and the cloud droplets evaporate from tiny liquid cloud droplets and into gaseous water vapor.