Aurora - Luminous phenomena that appear in the form of arcs, bands, draperies, or curtains in the high atmosphere over high latitudes. Auroras are related to magnetic storms and the influx of charged particles from the Sun. The phenomena are called aurora borealis in the Northern Hemisphere and aurora australis in the Southern Hemisphere.

Rain - Precipitation that falls to earth in liquid drops that are greater than 0.5 mm in diameter. Liquid drops that are smaller than .5 mm are categorized as drizzle. The largest raindrop that has ever been measured occurred in September of 1995 in Brazil as well as in July of 1999 in the Marshall Islands. At both these sites the raindrops were measured at a whopping 8.6 mm (.338 in) diameter!

Stratopause - The boundary or transition layer between the stratosphere and mesosphere. The stratopause is located around 30 miles above the surface of the earth.

Q Vectors - These vectors are calculated by meteorologists in order to find areas of the atmosphere with vertical ascent. They are an important tool because their interpretation allows meteorologists the ability to diagnose areas of lift in the vicinity of fronts as well as upper level jet streaks. Diagnosing lift is key to meteorologists because lift results in clouds and at times precipitation.

Frontolosis - The dissipation of a frontal zone due to a weakening contrast between two air masses. The temperature gradient weakens during frontolysis, meaning the rate of change of the temperature along the frontal boundary is lessening. At the end of frontolysis, the front no longer exists. The opposite of frontolysis is frontogenesis.

Cyclolysis - The process that occurs when a cyclone is weakening and decaying. At the end of cyclolysis, the cyclone has become extinct.

Thunderstorm - A local storm that spawns from a cumulonimbus cloud and is accompanied by lightning and thunder. The atmospheric conditions needed to produce a thunderstorm are warm and moist conditions in the low levels. It is estimated that around 1,800 thunderstorms are occurring on Earth at any given moment.