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.

Hiver - Hiver is the French word for winter.

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.

GFS (Global Forecast System) - One of the American operational forecast models run at the National Centers for Environmental Prediction. GFS stands for Global Forecast System. The GFS model is run 4 times a day and it covers the entire globe. GFS forecast output can extend up to 384 hours from when it is run.

Evapotranspiration - The sum of evaporation in which water is transferred from the land to the atmosphere. This includes moisture that evaporates from the soil and other moist surfaces, as well as moisture that is taken from plants due to transpiration.

Pluie - This is the french word for rain. To say, "it is raining today" one would say, "Il pleut aujourd'hui."

Coriolis force - An apparent force that is a result of the earth's rotation. When air currents develop, they are deflected to the right or left, depending on which hemisphere you are in. This is why low pressure systems and hurricanes in the northern hemisphere have winds that rotate counterclockwise around their center. In the southern hemisphere, low pressure system's winds rotate clockwise around their center.