Drought - An extended period of abnormally dry weather that creates shortfalls in the amount of surface and/or subsurface water. Droughts have major impacts on agriculture and can have major socioeconomic consequences as well.

Sub-vortices - Small areas of intense rotation located within a type of tornado called a multi-vortex tornado. These spinning whirls can be thought of as individual tornadoes that are mixed within the main tornado. These are also sometimes referred to as suction vortices and the winds within them can be 100 mph stronger than the main body of the tornado. These can explain why the damage path in a tornado can vary greatly.

Mesosphere - The mesosphere is a layer of the Earth's atmosphere located at an altitude of 30 to 50 miles above the Earth's surface. It is the layer where most meteors burn up upon entering the atmosphere. Because of this, there is a high concentration of iron and other metals in the mesosphere.

Turbulence - Any irregular or disturbed flow in the atmosphere caused by eddies and vertical air currents. Regions of the atmosphere that are characterized by turbulence will often be found in the vicinity of frontal boundaries. Thunderstorms produce the most severe turbulence due to the intense upward and downward vertical air currents that occur in the vicinity of them.

Stratus - A low, generally gray cloud layer with a fairly uniform base. Stratus clouds have the appearance of fog that doesn't reach the ground. These clouds tend to be associated with either no precipitation or light precipitation such as drizzle.

Fahrenheit - Temperature scale developed by the German-born scientist Daniel Gabriel Fahrenheit. The Fahrenheit scale bases the boiling point of water at 212 and the freezing point at 32. The U.S. and a few Caribbean countries still use the Fahrenheit scale. All other countries use the Celcius scale.

Occluded front - An occluded front forms when a mid-latitude cyclone's cold front catches up and merges with the warm front. This occurs due to the fact that cold fronts move faster than warm fronts. Once a low pressure system contains an occluded front, the low pressure system begins to weaken. The passage of an occluded front will feel like the passage of a cold front to an observer as cooler and drier air moves in behind an occluded front.