PLEA Network

23 April 2019, NOAA Climate.gov, The Pacific-North American Pattern: the stomach sleeper of the atmosphere. Some people like to sleep on their backs. Some people prefer to sleep on their stomachs or on their sides. Some people don’t sleep much at all! There are certain states we gravitate to when we sleep, often to maximize comfort. They are our preferred states. Would you be surprised if I were to tell you the atmospheric circulation operates in the same way, that certain patterns or flows appear more often than others because we’re not the only ones who like routine? One of these preferred states is the Pacific-North American Pattern, or as we scientists like to shorthand it: I know the presence of a fixed atmospheric pattern sounds a touch odd because most satellite loops of our planet show a fast, chaotic swirl of movement—weather fronts racing through the Plains, cyclones threatening the global tropics, and so on (check out the ever-mesmerizing GOES loops). There’s nothing particularly fixed-looking about it. But, if you slow it down, there are some quite enormous atmospheric flows that appear to be stuck on repeat. But they are not always present, and when they re-occur, they do so irregularly. Read more here