Progress in the Nationalization of National Weather Service Heat/Health Warning Systems

Excessive heat accounts for an estimated 1,500 deaths annually in the U.S. This is more than the number of deaths from Tornadoes, Hurricanes, Lighting, and Flash Floods combined.

NOAA's National Weather Service (NWS) currently issues a suite of excessive heat products to provide the Nation advance notice of excessive heat events for the protection of life and property. Today, these products are issued based on a single heat index value derived from temperature and humidity. Recent research has shown that often, a heat index value cannot fully predict when excessive heat becomes sufficient to stress a population causing a heat-related increase in mortality.

The NWS has implemented 16 HHWS and is planning to expand to each U.S. municipality with population exceeding 500,000. In all, greater than 70 U.S. cities meet the criteria. This paper will describe the implementation process and benefits of a national HHWS by the NWS.