An animation of nighttime images captured by the GOES-16 weather satellite on December 28, 2017. Long, parallel bands of cumulus clouds are seen streaming out over the Atlantic. (Images: RAMMB/SLIDER. GIF animation: Tom Yulsman) Baby, it's cold outside! If you live pretty much anywhere in Canada, or in the United States east of the Rockies, that wonderful song from the 1940s pretty much sums up the conditions as 2017 draws to a close. And when revelers watch the ball drop in New York City's Times Square on New Years Eve, they will have to endure forecast temperatures of 10°F – with a wind chill of -5°F. The brisk northwesterly winds that have carried the bitterly cold Arctic air have given rise to beautiful cloud formations over the Atlantic Ocean. You can see them in the animation of above, consisting of GOES-16 satellite imagery: long, parallel rows of cumulus clouds pouring to the southeast. These cloud formations are a well known phenomenon known as "cloud streets." This graphic from NOAA, along with the explanation from NASA's Earth Observatory, can help you visualize what's going on:
Source: NOAA Cloud streets are long parallel bands of cumulusclouds that form when cold air blows over warmer waters and a warmer air layer (temperature inversion) rests over the top of both. The comparatively warm water gives up heat and moisture to the cold air above, and columns of heated air called thermals naturally rise through the atmosphere. The temperature inversion acts like a lid. When the rising thermals hit it, they roll over and loop back on themselves, creating parallel cylinders of rotating air. As this happens, the moisture cools and condenses into flat-bottomed, fluffy-topped cumulus clouds that line up parallel to the direction of the prevailing winds.
