January 19, 2015 - Cloud streets off the eastern United States

Cloud streets off the eastern United States

A strong cold front brought bitter temperatures and heavy winds to the northeastern and Mid-Atlantic United States in early January 2015 – along with gorgeous patterns to the clouds offshore. According to Accuweather.com, residents along the northeastern and Mid-Atlantic coast started experiencing bitter wind chills on January 7, and the wind chills continued on January 8, the day that the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured this true-color image.

A frosty glaze of white snow covers the land from New Brunswick, Canada south to a well-demarcated line in northern Virginia, southern Maryland and mid-Delaware. Snow also covers West Virginia, west of the Appalachian Mountains. In the northwest, heavy white clouds obscure the land and most of the Great Lakes from view. Just offshore, from the mouth of the St. Lawrence River to Georgia, clouds line up in parallel rows, forming a truly extensive expanse of the formation known as “cloud streets”.

These cloud streets have been sculpted by the cold temperatures and prevailing westerly winds. When strong wind emerging from a cold surface blows over the warmer, moister atmosphere over the open ocean, cylinders of spinning air may develop in very regular, linear patterns. Clouds form along the upward cycle in the cylinders, where the air is rising, while skies remain relatively clear along the downward cycle, where air is falling. The result is a remarkably regular striped pattern of parallel lines in the clouds.

On January 8, the National Weather Service (NWS) reported air temperatures of 20 - 25⁰F below average, with wind chill values near zero in several areas, including New York City. The “wind chill” is a term used to describe the effect of wind on a body’s heat loss. At any given temperature, the higher the wind, the more heat is carried away from a human or animal body. High wind chills correlate to high wind speeds. According to Accuweather.com, a more quantitative measurement was made of sustained wind speeds over the Atlantic Ocean on January 7. High wind speeds just offshore were measured at 33.5 mph (54 km/h) and up to 44.7 mph (72 km/h) on January 7.

Image Facts
Satellite: Terra
Date Acquired: 1/10/2015
Resolutions: 1km (1.6 MB), 500m (6 MB), 250m (14.7 MB)
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC