Figure 5-4.-Formation of clouds due to mechanical lifting.
. Even though the positive area does not exceed
the negative area, cloudiness occurs after the parcel
passes the LCL, and precipitation may occur after the
parcel passes the ice crystal level.
One main advantage of this method is that it can be
done quickly and with relative ease. A major
disadvantage is that it assumes that the parcel does not
change its environment, and that it overestimates or
underestimates the stability and instability conditions.
INSTABILITY INDICATIONS FROM THE
A layer of the atmosphere is potentially unstable if
the potential wet-bulb temperature decreases with
altitude. Potential instability refers to a layer that is
lifted as a whole. The wet-bulb temperature may be
found by lifting each individual point on the sounding
dry adiabatically to saturation, and then back to its