Cold Front - A narrow zone of transition between relatively cold, dense air that is advancing and replacing warmer air out ahead of it.

Downburst - A strong wind that is the result of a strong downdraft that occurs beneath a severe thunderstorm. Downdrafts are pockets of air that accelerate downward from a thunderstorm, and then spread horizontally when they reach the ground. The resultant strong winds that are experienced at the surface is the downburst.

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.

Dew - Water that has condensed onto objects near the ground when the surface temperature of the object falls below the dew point. The most common surfaces that dew will form on are grasses and other vegetation. Dew can be an important source of moisture for plants during a drought.

Thermal Wind - The change in wind direction and speed with height of the geostrophic wind caused by a horizontal temperature gradient. This is a theoretical wind studied by meteorologists, but it is useful because it derives where major jet streams set up, such as the polar jet stream. For example, the area where temperatures vary the greatest from north to south over North America is where the polar jet stream will be found around 28,000 feet aloft.

Cryosphere - This term refers collectively to the portions of the Earth where water is in solid form. This includes areas with snow cover, floating ice, glaciers, ice caps, ice sheets, along with areas of frozen ground. The area of the cryosphere shrinks during the summer season and then grows during the winter.

Orographic Lifting - The forced rising of air that occurs when winds run into a mountain or any area with notably higher terrain. When moist air pushes against and rises up a mountain, the air cools adiabatically, resulting in clouds and precipitation. This is the reason why higher elevations in the mountains will see greater amounts of precipitation.