NCEP - NCEP stands for National Center for Environmental Prediction. This is a branch of the National Weather Service located in College Park, MD. NCEP is responsible for developing, running, and maintaining the main American computer models.

Synoptic Scale - In meteorology this refers to the study of large scale systems that develop in the atmosphere. Major cyclones and their associated fronts are a commonly studied feature in synoptic meteorology. In order to be on the synoptic scale, a system must stretch across a distance of at least 600 miles.

Colorado Low - A low pressure system that forms in eastern Colorado or northeastern New Mexico. These types of lows typically track northeastward across the central Plains of the U.S. over a period of several days. Some of the strongest blizzards that occur during the winter season are oftentimes the result of a Colorado low.

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.

Cold Air Advection - Cold air advection occurs when the wind blows from a region of cold air to a region where the air is warmer. This results in the transport of cold air by the wind. An area experiencing cold air advection can expect falling temperatures.

Rawinsonde - An instrument attached to a weather balloon that measures atmospheric pressure, temperature, humidity, and wind speed/direction at different layers of the atmosphere. As the instrument rises through the atmosphere, the data is sent via radio waves to a receiver on the ground. Rawinsondes are launched all over the world at specified times. The data from these launches is used in initializing the numerous forecast models.

Bermuda high - A semi-permanent subtropical high over the North Atlantic. Can contribute to excessive heat and humidity in the southern and eastern US. The placement of this high is also the main steering force for hurricanes that develop in the Atlantic.