3 Week Warning for Deadly Heat Waves

A recently identified atmospheric pattern may give people a two to three week warning that a deadly heat wave threatens to engulf the United States. Continue reading →

October 28, 2013
10:30 AM EDT
This map of air flow a few miles above ground level in the Northern Hemisphere shows the type of wavenumber-5 pattern associated with US drought. This pattern includes alternating troughs (blue contours) and ridges (red contours), with an "H" symbol (for high pressure) shown at the center of each of the five ridges. High pressure tends to cause sinking air and suppress precipitation, which can allow a heat wave to develop and intensify over land areas. (Haiyan Teng, National Center for Atmospheric Research)