The NWS defines the heat index as follows on its website:
The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature. This has important considerations for the human body’s comfort. When the body gets too hot, it begins to perspire or sweat to cool itself off.
Chart from NOAA showing relationship between relative humidity and temperature in heat index
Here is an excerpt from the hazardous weather outlook:
…HEAT ADVISORY IN EFFECT FROM NOON TODAY TO 8 PM EDT THIS
* WHAT…Heat index values up to and over 105 degrees expected.
* WHERE…Portions of central, east central, north central,
northeast, northwest, southeast and west central Georgia.
* WHEN…From Noon today to 8 PM EDT this evening.
* IMPACTS…Hot temperatures and high humidity may cause heat
illnesses to occur.
Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.
Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.
What time period does it cover?
The advisory is for noon to 8 p.m.
The following counties are listed in the outlook:
Dade, Walker, Catoosa, Whitfield, Murray, Chattooga, Gordon, Pickens, Dawson, Floyd, Bartow, Cherokee, Forsyth, Hall, Banks, Jackson, Madison, Polk, Paulding, Cobb, North Fulton, Gwinnett, Barrow, Clarke, Oconee, Oglethorpe, Wilkes, Haralson, Carroll, Douglas, South Fulton, DeKalb, Rockdale, Walton, Newton, Morgan, Greene, Taliaferro, Heard, Coweta, Fayette, Clayton, Spalding, Henry, Butts, Jasper, Putnam, Hancock, Warren, Troup, Meriwether, Pike, Upson, Lamar, Monroe, Jones, Baldwin, Washington, Glascock, Jefferson, Harris, Talbot, Taylor, Crawford, Bibb, Twiggs, Wilkinson, Johnson, Emanuel, Muscogee, Chattahoochee, Marion, Schley, Macon, Peach, Houston, Bleckley, Laurens, Treutlen, Stewart, Webster, Sumter, Dooly, Crisp, Pulaski, Wilcox, Dodge, Telfair, Wheeler, Montgomery, Toombs,
Including the cities of Calhoun, Rome, Cartersville, Gainesville,Marietta, Atlanta, Lawrenceville, Athens, Carrollton,Douglasville, East Point, Decatur, Conyers, Covington, Newnan,Peachtree City, Griffin, Milledgeville, Macon, Swainsboro,Columbus, Warner Robins, Dublin, Lumpkin, Americus, Cordele,and Vidalia
The National Weather Service (NWS) is a part of the National Oceanic and Atmospheric Administration (NOAA).
The NWS describes its role as follows:
The National Weather Service (NWS) provides weather, water, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy. These services include Forecasts and Observations, Warnings, Impact-based Decision Support Services, and Education in an effort to build a Weather-Ready Nation. The ultimate goal is to have a society that is prepared for and responds to weather, water and climate events.