Deposition - The process where water turns directly from vapor to ice, without first becoming liquid. A common instance of deposition is when frost forms on the grass during cold mornings.

Freezing Rain - Rain that falls as a liquid but freezes into glaze upon contact with the ground. Freezing rain occurs when there is a temperature profile in which the air above the surface is above 32 degrees, while the surface temperatures are sub-freezing. Freezing rain accumulates on roads, trees, power lines, and any other surfaces near the ground. Power outages are common during severe freezing rain events.

Hydrosphere - The hydrosphere is composed of the sum of all the water on Earth. This includes all the Earth's surface waters such as oceans and lakes, as well as all sources of frozen water. Water vapor and therefore clouds are also included in the hydrosphere.

Nautical Twilight - Is defined to begin in the morning, and to end in the evening, when the center of the sun is geometrically 12 degrees below the horizon. At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other illumination, general outlines of ground objects may be distinguishable, but detailed outdoor activities are not possible. During nautical twilight the illumination level is such that the horizon is still visible, even on a Moonless night, thereby allowing mariners the ability to take reliable star sights for navigational purposes.

Dust Bowl - An extended period of exceptional drought that affected the Great Plains of North America during the 1930s. Agricultural activities were crippled during this epic drought. Heat waves and occasional dust storms were fairly common during the dust bowl years. On some occasions, the dust storms in the Plains made it all the way to the east coast.

Rossby waves - Also known as planetary waves. Rossby waves are a series of long-wavelength troughs and ridges that occur along the main branches of the jet stream. They form due to the rotation of the Earth and are an important way for the planet to distribute heat away from the equator as well as cold air from the poles.

Freezing Fog - Freezing fog occurs when the water droplets that the fog is composed of are supercooled. Supercooled water droplets remain in the liquid state until they come into contact with a surface upon which they can freeze onto. As a result, any object that freezing fog comes into contact with can become coated with ice. Freezing fog can make for treacherous driving conditions due to limited visibility combined with icy patches that can develop on the road.