From April 14 to 16, 2011, a powerful weather system moved across the U.S. Midwest, South and East, spawning severe storms and nearly 250 tornadoes and resulting in widespread destruction and dozens of fatalities. The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured an infrared image of the storms on April 16, 2011, at 18:29 UTC (2:29 p.m. EDT). The image showed very cold, high cloud tops of the strong thunderstorms that spawned tornadoes in North Carolina and Virginia. The coldest cloud tops (purple) indicated the strongest storms. Temperatures in those clouds were as cold as or colder than minus 63 degrees Fahrenheit/minus 52 degrees Celsius.
NOAA's Storm Prediction Center noted that the system generated 243 tornadoes in 13 states between April 14-16. According to the Weather Channel, the weather system generated 29 tornadoes on April 14 across the states of Oklahoma, Kansas, Arkansas and Texas. As the storm moved east, 73 tornadoes touched down in Alabama, Mississippi, Illinois, Arkansas, Kentucky, Missouri and Louisiana on April 15. On Saturday, April 16, 51 tornadoes were reported in North Carolina, Virginia, South Carolina, Alabama, Georgia and Maryland. Alabama, Mississippi, North Carolina and Virginia have all declared a state of emergency.
When the front swept through North Carolina on Saturday, April 16, the National Weather Service confirmed six tornadoes hit the central part of the state. Reports of tornadoes came from Alamance, Cumberland, Lee, Person and Wake counties. The National Weather Service in North Carolina has confirmed the strength of six different tornadoes that hit the state during the outbreak. They are working on confirming other possible tornadoes, as teams survey more damaged areas in the state. Two of the tornadoes were powerful EF3s with estimated winds near 160 miles per hour. One of those tornadoes traveled through Hoke, Cumberland and Harnett counties while the other powerhouse traveled through Lee and Wake counties causing damage in their wake. The two EF3s had paths that stretched more than 60 miles, according to the National Weather Service. A less powerful, but destructive EF2 tornado tracked through Wilson County, while EF1s affected Johnston and southeastern Cumberland and Sampson County. Person County had a touchdown of an EF0 twister.
The Atmospheric Infrared Sounder, AIRS, in conjunction with the Advanced Microwave Sounding Unit, AMSU, senses emitted infrared and microwave radiation from Earth to provide a three-dimensional look at Earth's weather and climate. Working in tandem, the two instruments make simultaneous observations all the way down to Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, three-dimensional map of atmospheric temperature and humidity, cloud amounts and heights, greenhouse gas concentrations, and many other atmospheric phenomena. Launched into Earth orbit in 2002, the AIRS and AMSU instruments fly onboard NASA's Aqua spacecraft and are managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
More information about AIRS can be found at http://airs.jpl.nasa.gov.