Instability, high moisture content, and a
lifting force cause thunderstorms. Their formation is promoted
when warm moist air is lifted, cools and condenses, releasing more heat. Hazards
commonly include hail, turbulence, and lightning. Of the three types of
thunderstorms: two are associated with airmass characteristics and one is of a
frontal nature. Air Mass thunderstorms are cause by convection
or when the air mass is lifted over an obstruction such as a mountain. They are
usually localized such that they can be fly flown around. Frontal
thunderstorms are due to a cold front or are embedded in a warm front.
This type can extend for hundreds of miles. The general characteristics of
thunderstorms are cells 5-30 miles diameter, last typically 20 minutes-1.5
hours, have a cumulus stage of updrafts, a mature stage of precipitation,
updrafts, downdrafts and strong vertical shear, and a dissipating stage with
downdrafts.