Microscale - Microscale meteorology is the study of small and/or short-lived atmospheric phenomenon. This study of small-scale weather systems includes tornadoes, rainbows, and thunderstorm updrafts and downdrafts.

Sublimation - Any process where a solid turns directly into a gas. In meteorology, this term is used to describe the process by which ice turns to water vapor. This process can be seen when observing the behavior of dry ice. Dry ice is actually frozen carbon dioxide that turns to carbon dioxide gas when it breaks down.

Rain Gauge - An instrument used to measure the amount of rainfall that occurs over a specific site. A standard rain gauge can measure up to 8 inches. The first known device that was used for measuring rainfall was invented in Korea in 1441.

Hook Echo - A distinctive radar pattern that has the appearance of a hook extending from the radar echo. A hook echo indicates that the thunderstorm's updraft is rotating. This rotating updraft is called a mesoscyclone. These types of thunderstorms are called supercells and present the greatest risk for tornadic activity.

Advection Fog - Advection fog often looks like radiation fog and is also the result of condensation. However, the condensation in this case is caused not by a reduction in surface temperature, but rather by the horizontal movement of warm moist air over a cold surface. This is very common during the winter when warm moist winds blow over cold snowcover. Advection fog may also form when moist maritime air masses drift over a cold inland area. This usually happens at night when the temperature of the land drops due to radiational cooling.

Mist - A visible collection of tiny water droplets suspended in the atmosphere that can reduce visibility to as low as 5/8 of a mile. It does not reduce visibility as much as fog and is often confused with drizzle. Drizzle falls to the ground, while mist hangs in the lower atmosphere.

Tropopause - Zone of the atmosphere that marks the transition between the troposphere below and the stratosphere above. The tropopause is the top of the troposphere. 75 percent of the mass of the atmosphere is located below the tropopause. The height of the tropopause varies between 4 to 12 miles.