Produced by: Tarun Mishra
Mexico has been grappling with a severe heatwave due to a heat dome, which has now extended into the southern United States, causing extreme temperatures across a vast region.
While not a precisely defined scientific term, a heat dome refers to an exceptionally hot air mass that forms when high pressure aloft prevents the warm air below from rising. This phenomenon is commonly used by weather forecasters.
According to the American Meteorological Society, high-pressure systems result in clear skies as descending air warms. Clouds, which form under opposite conditions with rising, cooling air, are absent.
High-pressure conditions lead to prolonged sunshine, which further warms the air and dries out the soil. Reduced evaporation lowers the chances of cloud formation and rain, creating a feedback loop that intensifies heat.
While heat domes can cause heatwaves, not all heatwaves result from heat domes. Heatwaves can occur under different meteorological conditions.
Jet streams, which are fast-flowing bands of wind in the upper atmosphere, typically move weather systems. However, sometimes these streams form large loops, causing weather systems, including heat domes, to get stuck.
These looping patterns in the jet stream, known as blocking patterns, can lead to prolonged extreme weather, whether it be extreme cold, rain, or heat, as seen with heat domes.
As the climate changes, the frequency and intensity of heat domes may increase. Understanding these phenomena and their impacts is crucial as the planet continues to warm.