Clear Slot - In respect to severe thunderstorms, a clear slot is a local region of clearing skies or reduced cloud cover. This oftentimes indicates that there is an intrusion of drier air, oftentimes noted by a bright area with higher cloud bases on the west or southwest side of a wall cloud. A clear slot is believed to be a visual indication of a rear flank downdraft

Wedge tornado - A term used by observers that indicates that the tornado looks wider than the distance from the ground to the cloud base. Essentially, it is a slang term to describe a very wide tornado. Rather than having the typical funnel shape, a wedge tornado often appears as a large, flat cloud reaching the ground. These are often-times multi-vortex tornadoes, where large amounts of dirt and debris can conceal the individual funnels.

Eddy viscosity - The turbulent transfer of momentum by eddies giving rise to internal fluid friction. Eddy viscosity is an important concept in turbulence theory.

Arctic Front - The semi-permanent, semi-continuous boundary that separates the deep, cold arctic air from the shallower, less frigid polar air of the northern latitudes. Major shifts in the polar jet stream can drive arctic fronts southward into the mid-latitudes during the winter season.

Radiation Fog - This type of fog forms at night under clear skies with calm winds. Under these conditions heat that was absorbed by the earth's surface during the day is allowed to radiate back into space. As the earth's surface continues to cool, provided a deep enough layer of moist air is present near the ground, the humidity will reach 100% and fog will form. Radiation fog varies in depth from 3 feet to about 1,000 feet and is always found at ground level and usually remains stationary. This type of fog can reduce visibility to near zero at times and make driving very hazardous.

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.

Rossby waves - Also known as planetary waves. Rossby waves are a series of long-wavelength troughs and ridges that occur along the main branches of the jet stream. They form due to the rotation of the Earth and are an important way for the planet to distribute heat away from the equator as well as cold air from the poles.