Why the Weather on the Great Plains Is So Extreme
It can be tough to live on the Great Plains. The flat terrain gives way to breathtaking views of both land and sky, but the smooth, fertile land is both good fortune and a curse when it comes to the weather. Whether it's an enormous thunderstorm or a ferocious blizzard, there's rarely a dull day when it comes to weather in the middle of the country. Just what is it about the central United States that makes the weather there so extreme?
The unique geography that makes this part of the country so grand is what exposes it to some of the most extreme weather nature can produce. The Plains are bounded by the Rocky Mountains to the west, the Canadian Prairies to the north, and the Gulf of Mexico to the south. The tall, jagged mountains of the Rockies act like an atmospheric dam, forcing hot air from the south and cold air from the north to pool up over the Plains. This helps to trigger some of the most interesting weather in the world.
Most major weather events around the world are set in motion by jet streams, which are fast-moving currents of air that wrap around the planet. Straight, rigid jet streams don't result in much interesting weather, but things can get wild when the jet stream grows wavy. Sharp dips in the jet stream, called troughs, can cause low-pressure systems to develop at the surface.
When these troughs clear the Rocky Mountains in the western U.S., diverging winds in the upper atmosphere cause air to rise from the surface, leading to the development of a low-pressure system over the Plains. These lows can be the size of a single state or sprawl across the entire country from north to south. We see these storm systems most often during the winter and spring, when the jet stream is most active over the United States.
The flat land acts like an expressway, helping these fledgling low-pressure systems draw enormous amounts of tropical air from the south and, during the winter, extremely cold air from deep in the Arctic. The lack of natural obstacles allows this air to flow toward storm systems virtually unimpeded, which can lead to explosive thunderstorms during the warm months and powerful and bone-chilling blizzards during the winter.
This atmospheric expressway doesn't stop at precipitation; it's also why the central Plains can have brutal heat waves and bitter cold snaps. It's not uncommon for areas in the north-central United States to struggle to climb above 0°F for days at a time during the dead of winter, and it's similarly common for places like Oklahoma and Texas to see temperatures above 100°F for a week or longer during the summer's worst heat.