Hi Capt Lim,
Can you tell me the different category of thunderstorm?
There are various categories of typhoons and turbulence but I have not come across a well defined category of thunderstorm other than whether it was "strong" or "severe".
The National Weather Service (NWS) defines a "severe" thunderstorm as having winds of 58 mph or faster or hail of more than three-quarters of an inch in diameter or both. The NWS has no formal definition of a "strong" thunderstorm. The term is the subjective opinion of a forecaster or someone experiencing the storm. The strength of a thunderstorm is judged by the intensity of the thunder and lightning or by its precipitation.
Thunderstorms aren't specifically classified in the same way that tornadoes or hurricanes do. So the only real classification the U.S. National Weather Service uses for thunderstorms is whether they are or they are not.
Weather wise, severe thunderstorms are a pilot's worst nightmare. They cause major air traffic delays because pilots strive to avoid them. Lines of thunderstorms cause airplanes to make long detours around them while storms near airports can prevent takeoffs and landings because they give rise to micro bursts and wind shears.
Thunderstorm dangers include fierce updrafts and downdrafts. These cause extreme turbulence that makes an airplane hard to control. Near the ground, thunderstorms sometimes create quick changes in wind speed and direction known as wind shear which has caused several crashes.
Hailstones associated with thunderstorms can heavily damage airplanes, including breaking windshields and turbine blades of jet engines. Rain from the thunderstorm can sometimes be heavy enough to drown jet engines.
Lightning is also associated with thunderstorms and they can temporarily blind pilots. It also regularly hits airplanes and can damage electronic equipment but so far, I believe, only one airline crash on a Boeing 707 in the USA in 1963 is known to have been caused by lightning.