Blue Jet - An upper-level atmospheric electrical discharge, usually blue or bluish-white in color, that occur high above thunderstorms. Similar to sprites. This phenomenon is believed to connect the tops of thunderstorms with the ionosphere.

Noctilucent Clouds - These are a type of cloud that is extremely rare and found very high in the atmosphere. The base of these clouds is typically around 200,000 feet. They are seen as wavy, thin, bluish-white clouds and are best seen at twilight in polar latitudes. The word Noctilucent is derived from the latin word that means "night-shining.'

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.

Smog - The first definition of smog was a mixture of smoke and fog in the atmosphere which reduces visibility. Over time smog has now changed its meaning to restricted visibility due to pollution emitted from human activities. A type of smog known as photochemical smog, common to heavily populated areas, forms when UV light from the sun reacts with low level pollutants such as nitrogen oxides. On hot days this reaction can create ozone gas at the surface which is dangerous to humans.

Lee-Side - The term lee-side in general refers to the sheltered side from the wind. In weather, this term is used when referring to the sides of a mountain range. The side that takes the prevailing winds first is known as the windward side, while the side opposite the prevailing winds is the lee-side. The lee-side of the Rocky Mountains is to the east of the mountain range.

Barometer - An instrument used to monitor variations in air pressure at the surface. The first barometer was invented by the Italian physicist Torricelli in 1643. For the centuries to follow, the barometer was the main tool used in weather forecasting.

Upslope Fog - A type of fog forms when light winds push moist air up a hillside or mountainside to a level where the air cools adiabatically to the point that it reaches saturation. At this point water vapor condenses into water droplets, thereby forming a layer of fog.