Weather Word of the Day
October 23, 2019
Hadley cell -
A thermally driven air circulation in tropical and subtropical latitudes of both hemispheres. The Hadley cell resembles a huge convective cell with rising air near the equator and sinking air in the subtropical latitudes. This concept was first introduced by George Hadley in 1735.
October 22, 2019
St. Elmo's fire -
A bright electric discharge that is projected from objects when they are in a strong electric field, such as during a thunderstorm.
October 21, 2019
The process by which water changes phase from a liquid to a vapor. Energy from the sun and wind are the main drivers of evaporation. 80% of evaporation occurs over the oceans, while the remaining 20% occurs over land. The highest evaporation rates occur when the relative humidity is low on a hot and windy day.
October 20, 2019
Cirrocumulus clouds -
These high clouds are noted by small rounded white puffs composed of ice crystals. When the sky is covered by these clouds the sky can look like the scales of a fish, and is called a mackerel sky. These clouds are common during the cold season, and often indicate fair but chilly weather conditions.
October 19, 2019
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.
October 18, 2019
Air mass -
A generic term for describing areas of the atmosphere that have similar origins, along with similar temperature and moisture qualities. The two main types of air masses are tropical and polar. Polar air masses are typically cold and dry, while tropical air masses are inherently warm and humid.
October 17, 2019
The dissipation of a frontal zone due to a weakening contrast between two air masses. The temperature gradient weakens during frontolysis, meaning the rate of change of the temperature along the frontal boundary is lessening. At the end of frontolysis, the front no longer exists. The opposite of frontolysis is frontogenesis.