The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft captured this infrared image of the first of a series of storms approaching the Pacific Northwest at 2141 UTC (1:41 p.m. PST) on Nov. 28, 2012, marking the beginning of an "atmospheric river" event. Atmospheric rivers are narrow regions in Earth's atmosphere that channel and transport enormous amounts of water vapor across the Pacific or other regions. Areas of deep blue and violet mark the highest and coldest cloud tops, the result of strong convection and the location of precipitation. The flow of moisture (nicknamed the "Pineapple Express") visible south of the low pressure system is expected to intensify the rainfall, causing very heavy rains and possible flooding as well as debris flows in the mountainous burn areas of Northern California.

AIRS is managed by NASA's Jet Propulsion Laboratory, 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.