Unstable Air
An air parcel is considered unstable if it is warmer than the surrounding air. When this occurs the air parcel will rise since it is less dense than the air surrounding it. In an unstable environment, the weather can change suddenly and can be rather violent.
Good Visibility
Within an unstable layer of air, smoke and industrial pollutants are more readily mixed within the atmosphere and are not trapped within lower levels as would be the case in a stable layer of air. As a result, within an unstable air mass visibility is generally good outside areas of precipitation.
Cumuliform Clouds
Cumulous clouds or clouds with vertical development are generally associated with an unstable air mass. If sufficient moisture is present, cumulus clouds may develop into cumulonimbus clouds.
Turbulent Air
Because of the vertical motion of air, flight in an unstable airmass is, for the most part, associated with light to moderate turbulence.
Showery Precipitation
Showery precipitation is associated with an unstable air mass. A shower is a mode of precipitation characterized by an abrupt start and end and by rapid variations in intensity. Often strong and short-lived, it originates from convective clouds.
