A word of caution, the following might be little heavy on scientific detail for some people. However, for those fascinated by the extreme forces of nature, please read on.

Instability: Instability is a condition in which air will rise freely on its own due to positive buoyancy. As an example, imagine a beach ball at the bottom of a swimming pool. Once the beach ball is released, it accelerates upward to the top of the pool. The beach ball rises because it is less dense than the water surrounding it. A similar process occurs when instability is released in the atmosphere. Air in the lower part of the atmosphere is lifted until it becomes less dense than surrounding air. Once it is less dense, it rises on its own. The speed that is rises depends on the density difference between the air rising and the surrounding air. In a thunderstorm, this rising air is called an updraft. It is the updraft of a storm that allows it to grow and sustain itself as it feeds on low-level moisture.

Vertical Wind Shear: First, it is important to note that there are two types of vertical wind shear. The first is called “vertical speed shear” and is a significant increase in wind speed with height. The second is called “vertical direction shear” and is a significant change of wind direction with height. Both of these are important in the development of severe storms for several reasons. A significant increase of wind speed with height will tilt a storm's updraft. This allows the updraft and downdraft to occur in separate regions of the storm allowing the storm to have a longer life span. Strong upper atmospheric winds, associated with the jet stream, allow the updraft of the storm to sustain itself while keeping the storm fed with low-level moisture. Directional shear in the lower part of the atmosphere helps initiate the development of a rotating updraft. This is one of the most important factors in determining whether a storm will be capable of producing a tornado or not.

Lift: While instability release is like a beach ball rising from the bottom of a swimming pool, lift occurs when air is forced to rise. Newton’s first law states that an object at rest will remain at rest unless acted upon by an outside force. The same is true when referring to lift in the atmosphere. Often times the air near the surface will not rise unless acted upon by an outside force. This outside force is called a lifting mechanism. A lifting mechanism is needed to force air near the surface to initially rise. Without a lifting mechanism, parcels of air will not reach the point in the atmosphere where they can rise on their own due to positive buoyancy. Therefore, despite having sufficient instability in the atmosphere, it will not be released without a lifting mechanism. Some lifting mechanisms include; Frontal Boundaries (like cold fronts or warm fronts), Upper Level Disturbances, Orographic Lifting (upslope flow associated with higher elevations), Low Level Warm Air or Moisture Advection (the transport of warmer temps or higher amounts of moisture by the wind), and Low Pressure Systems.

Moisture: Low-level moisture is the fuel to which a thunderstorm feeds off of. While dew point temperature is a measure of how much moisture is in the air, severe thunderstorms are more likely when the surface dew point is generally 55 F or higher. Low dew point values inhibit sufficient energy release in the atmosphere and significantly reduce the threat of severe storms. The depth of moisture in the lower troposphere and the rate of moisture advection are also important. While a lack of moisture in the lower atmosphere reduces the severe storm threat, a lack of moisture in the middle of the atmosphere can actually increase the threat of severe weather. Dry air in the middle layers of the atmosphere can act as a lid helping to increase amounts of heat and moisture at the lower levels. This low level heat and moisture is often released suddenly with the help of a lifting mechanism creating explosive thunderstorm development. The advection of low-level moisture brought by the wind can aid in a thunderstorm’s growth by increasing the amount of fuel available for the storm to feed off of.