Severe Thunderstorm Watch - This is issued by the National Weather Service when conditions are favorable for the development of severe thunderstorms in and close to the watch area. A severe thunderstorm by definition is a thunderstorm that produces one or more of the following: 1 inch hail or larger in diameter, winds equal to or exceeding 58 miles an hour, isolated tornadoes. The size of the watch can vary depending on the weather situation. They are usually issued for a duration of 4 to 8 hours. A watch doesn't mean severe weather is occurring, but it does mean that severe thunderstorms are possible in the watch area.

Advection - The transfer of an atmospheric property by wind. The most common entities that meteorologists look at when diagnosing areas of advection are temperature and moisture.

Cap Cloud - A stationary stratiform cloud that forms directly above an isolated mountain peak. This type of cloud develops when moist air pushes against the mountain and is forced upward. As the air rises it eventually cools enough for the water vapor to condense and form a cloud.

Parhelion (Sun dog) - The scientific name for sun dogs. This phenomenon is seen as two colored luminous spots that appear at roughly 22 degrees on both sides of the sun at the same elevation. They are caused by the refraction of sunlight passing through ice crystals. They are most commonly seen during winter in the middle latitudes and are exclusively associated with cirriform clouds. They are also known as mock suns.

Aurora Borealis - Also known as the northern lights; these luminous radiant emissions from the upper atmosphere can be seen over middle and high latitudes. They are centered around the earth's magnetic poles. These silent fireworks are often seen on clear winter nights in a variety of shapes and colors.

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.

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