Thunderstorms are one of the most beautiful atmospheric phenomenon and also are one of the most hazardous conditions that producesevere turbulence, low level windshear, low ceilings and visibilities, hail and lightning .
Thunderstorms are formed by a process called convection, defined as the transport of heat energy. Because the atmosphere is heated unevenly, an imbalance can occur which thunderstorms attempt to correct.Three things are needed for convection : moisture, lift and instability .
Moisture—Sufficient moisture must be present for clouds to form. Although convection occurs in the atmosphere without visible clouds, think thermalson a warm afternoon, moisture not only is the source of a visible cloud, butalso fuels the convection to continue
. As the warm air rises, it cools, and thewater vapor in the air condenses into cloud droplets. The condensation releases heat, allowing
the rising air to stay buoyant and continue to move upward.
Lift—There are many ways for air to be lifted in the atmosphere. Convection,or buoyancy, is one method. Other meteorological methodsinclude fronts,low pressure systems, interactions between thunderstorms, and interactions between the jet stream and the surfaceweather systems. Air also can be lifted by mechanical lift,such as when it is forced up and over a mountain range.Regardless
of how the air is lifted, if the lift is enough to make the air warmer than the surrounding air, convection can continue.
Instability—In general, as you increase in altitude, the air temperature cools up to the top of the troposphere. Of course, around fronts, mountains and in shallow layers near the ground, this is not always the case.How fast air cools is a measure of atmospheric stability . Meteorologists refer to this vertical change in temperature as the lapse rate.Outside of extremes, the temperature generally decreases from between 2.7oF - 5.4oF per 1000 feet. If the actual rising air cools slower than the lapse rate, the air remains relatively warm to compared the surroundings, and it continues to rise.