A giant white comma has taken shape off the western U.S. coast.

Though,Watch Sukeban Deka: The Movie Online technically, it's a common winter storm called a mid-latitude cyclone, so large it will impact much of the country while dousing many regions with rain or snow. The NASA image above shows the storm in a nicely mature stage, after it developed over the Pacific Ocean.

"It's a classic mid-latitude cyclone," said Jeff Weber, a research meteorologist at the University Corporation for Atmospheric Research.

A mid-latitude cyclone is quite different than a tropical cyclone (like hurricanes) which form near the equator and are fueled by really warm, bath-like surface ocean temperatures.

Instead, these mid-latitude cyclones are much larger (some 900 to over 3,000 miles in diameter) than tropical cyclones and can impact an entire continent, explained Weber. They form near the boundaries of the frigid poles and the warmer air of the mid-latitudes. These converging air masses create counter-clockwise circulating motions that can induce whirlpool-like movement. Add the energy from some typical atmospheric instability to the mix (like rising and sinking air), and you've got a robust, spinning storm.

At its most basic level, a mid-latitude cyclone is air and clouds swirling around a region of low atmospheric pressure.

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This particular mid-latitude cyclone picked up bounties of moisture as the storm traveled down from Alaska's Aleutian Islands through warmer, and consequently more moist, air. The storm will douse California before continuing across the rest of the country. "It's forecast to roll through the U.S.," said Weber.

Advanced satellite imagery, like the National Oceanic and Atmospheric Administration's (NOAA) GOES-16 and GOES-17 satellites, allow meteorologists like Weber to follow cyclones in closer-than-ever detail as they circulate around the globe.

"It's a wonderful time to be alive," said Weber.