Many of the latest buzzwords in weather forecasting—“polar vortex,” “bomb cyclone”—describe natural phenomena that are not new, or even necessarily more common than before, even as climate change has generally led to to more climatic extremes. But the terminology is in wider circulation, sometimes accurately, sometimes less so.
Polar vortex
According to the National Weather Service, a polar vortex “It is a large area of low pressure and cold air that surrounds both poles of the Earth. It ALWAYS exists near the poles, but it weakens in summer and strengthens in winter. The term ‘vortex’ refers to the counterclockwise airflow that helps keep cooler air near the poles. The polar vortex expands fairly regularly during the Northern Hemisphere winter, carrying air from the Arctic toward the United States.
cyclone pump
A bomb cyclone is a rapid drop in pressure in a low-pressure air mass, “of at least 24 millibars in 24 hours,” he said. John Gyakum, a McGill University meteorologist who helped coin the term in the 1980s. As the pressure difference, or gradient, between the low-pressure air mass and the neighboring higher-pressure air mass grows, winds increase sharply. This rapidly escalating process is known as bombogenesis.
atmospheric river
atmospheric rivers “They are narrow regions in the atmosphere that transport much of the moisture from the tropics to the 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 risks.”
Some atmospheric rivers can cause hazardous weather conditions, but many others can’t, Dr. Gyakum said, adding: “Many of these cases can just move and wander around the world and not do much.”
quick pineapple
A semi-famous example of a strong atmospheric river is the Pineapple Express, so named “because moisture accumulates in the tropical Pacific around Hawaii and can batter the western coasts of the US and Canada with heavy rain and snow.” according to NOAA.
(In 2008, Seth Rogen starred in a comedy film called “Pineapple Express,” in which a drug dealer witnesses a murder and is on the run from a murderer and a crooked police officer, but it hasn’t had a discernible impact on the weather).
ARkStorm
A “‘megastorm’ scenario” that was originally projected to occur once every 1,000 years, according to the United States Geological Survey, but now “it is projected to be more frequent and intense as a result of climate change.” The name comes from combining “AR” (atmospheric river) and “k” (for 1000). One such megastorm occurred in California in 1861-62, “and there is no reason to believe that similar events will not occur again,” according to the agency.
