PILOT’S
GUIDE
41
STRIKE FINDER
DIGITAL WEATHER AVOIDANCE
Figure 35.Thunderstorm Development
Thunderstorm Stages
The life cycle of a thunderstorm includes three stages: cumulus, mature,
and dissipating.
Cumulus Stage
— is the beginning of all thunderstorms. The size of the
updraft region (cell) becomes larger and the cloud grows in an unsteady
succession of upward bulges, as evident by the thermals that reach to the
top. Strong vertical winds, severe turbulence, icing and lightning, are
typical hazards that an aircraft could encounter at this stage.
Mature Stage
— is reached when the precipitation-induced downdraft
reaches the ground. Heavy rain or hail, and in colder areas sleet or snow,
are driven by strong downdrafts. Wind shear, lightning and thunder develop
as a result of friction between the opposing air currents. At this stage the
hazards can be devastating for any aircraft.
Dissipating Stage
— is reached when the updraft is overwhelmed by the
precipitation induced downdraft.With no source of moisture, the associated
hazards decrease and the entire thunderstorm gradually dissipates.
Strike Finder Pilot's Guide fix 9/19/05 10:59 AM Page AT