Polar Vortex, Bomb Cyclone and Other Weather Terms, Explained

A handy explanation of some of the new climatological verbiage.

Many of the latest buzzwords in weather forecasts - "polar vortex", "bomb cyclone" - describe natural phenomena that are not new, or even necessarily more common than before, even though climate change, in general, has led to more extreme weather events. But the terminology is more widely disseminated, sometimes precisely, sometimes less.

Polar Vortex

According to the National Weather Service, a polar vortex "is a large area of ​​low pressure and the cold air surrounding the two poles of the Earth. It ALWAYS exists near the poles, but weakens in the summer and strengthens in the winter. The term "vortex" refers to the counter-clockwise flow of air. "a watch that helps keep the air colder near the poles. The polar vortex develops quite regularly during the winter in the northern hemisphere, carrying arctic air towards the United States.

Bomb Cyclone

A cyclone bombardment is a rapid pressure drop in a mass of pressurized air - "by at least 24 millibars in 24 hours," said John Gyakum, a meteorologist at the 'McGill University who helped coin the term in the 1980s. As the pressure difference, or gra dient, increases between the low-pressure air mass and the neighboring high-pressure air mass, the winds intensify sharply. This process of rapid intensification is known as bombogenesis.

Atmospheric river

Atmospheric rivers "are narrow regions of the atmosphere that carry much of the 'humidity from the tropics to northern latitudes'. according to the National Oceanic and Atmospheric Administration, or NOAA. "Atmospheric rivers are part of the water cycle of Earth's oceans and are closely linked to both water supply and flood risk."

Some atmospheric rivers can cause dangerous weather conditions, but many others don't, Dr. Gyakum said, adding: "A lot of these can just move and meander around the globe and not make it big -thing at all."

Pineapple Express

A semi-famous example of a strong atmospheric river is the Pineapple Express, so called "because the humidity accumulates in the tropical Pacific around Hawaii and can hit the west coasts of the United States and Canada with heavy rain and snow," according to NOAA.< /p>

(In 2008, Seth Rogen starred in a comedy called "Pineapple Express", in which a drug dealer witnesses a murder and flee from an assassin and a corrupt cop, but it had no discernible impact over time.)

ARkStorm

A "'megastorm' scenario" that was originally intended to occur once every 1,000 years, according to the United States Geological Survey, but is now "expected to become more frequent and more intense due to climate change". The name comes from the combination of "AR" (atmospheric river) and "k" (for 1000). One such megastorm occurred in California in 1861-1862, "and there is no reason to believe that similar events will not occur again," according to the agency.