Thunderstorms are one of the most dangers weather phenomenon's for aircraft.
Formation:
For thunderstorms to form there are three sufficient things that must be present. They are:
Sufficient water vapor
Unstable conditions
Initial lifting action
Thunderstorms can reach altitudes as high as 50,000 – 60,000 feet. It is not usual for thunderstorms to grow as high as 75,000 feet, especially in the tropic areas. The taller the thunderstorm is the more dangerous and intense it is.
Lift Cycle:
There are three stages to a thunderstorm life cycle, they are:
Cumulus stage – The beginning stage of the storm has strong updrafts or the lifting action of moist air to create the formation of cumulonimbus clouds.
Mature stage – It takes approximately 15 minutes to reach this stage. Moisture falls in the form of rain or hail, along with downward and updraft air creating strong turbulence. When vertical motion of air begins to slow down the top forms an anvil shape and begins the next stage.
Dissipating stage – The final stage of the storm has downdrafts or downward motion of air, which intensifies and spreads out. It is also the sign that the storm is dying out.
Avoidance:
Small aircraft cannot fly over a thunderstorm. Flying under a thunderstorm is NEVER a good idea, due to strong downdrafts, violent turbulence, lightning, hail, etc.
The anvil at the top of the Thunderstorm is a good indicator, to which direction the storm is moving. When trying to avoid a thunderstorm during flight, fly to the opposite side of the anvil direction, by 20NM or more.
The safest way to avoid thunderstorms is to, NOT fly at all and just wait it the storm out on the ground.
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