Weather Service launches new index for hot weather alerts

A kid runs through splashing water at the Centennial Olympic Park fountains as temperatures rise on Thursday, June 13, 2024. 
(Miguel Martinez / AJC)

Credit: Miguel Martinez

Credit: Miguel Martinez

A kid runs through splashing water at the Centennial Olympic Park fountains as temperatures rise on Thursday, June 13, 2024. (Miguel Martinez / AJC)

In the spirit of weather watches and warnings, the National Weather Service is testing a new alert system for dangerous heat conditions.

The HeatRisk tool is an “experimental color-numeric-based index that provides a forecast risk of heat-related impacts to occur over a 24-hour period,” according to the organization.

Credit: National Weather Service

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Credit: National Weather Service

The Weather Service has a 5 point HeatRisk scale, with numbers and colors:

0 or Green: Little to no risk from expected heat.

1 or Yellow: Minor risk.

2 or Orange: Moderate risk.

3 or Red: Major health risk from hot weather.

4 or Magenta: Extreme conditions. This rating should be used rarely, the Weather Service said.

The Weather Service acknowledges that it gets hot in the summer, so this tool is beyond that. It attempts to flag conditions that are unusually hot for the time of year in your location. For example, will it be warmer than the highest recorded temperatures for a day or a week? The scale also factors in humidity, which can increase risk of health issues, or the presence of unusually warm overnight temperatures.

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Learn more about the HeatRisk tool and check the current rating for Atlanta or Georgia

From the CDC: Heat and Health Tracker and a separate page on preventing heat-related illness

About the HeatRisk tool:

How unusually above normal the temperatures are at your location (is it warmer than the top 5% of hottest days in the period of record for this date?)

The time of the year (for example, is this early season heat that you likely haven't become used to, typical mid-summer heat, or late season heat that you may have become more used to?)

The duration of unusual heat (for example, are temperatures overnight at levels that would lower heat stress, maintain it, or will unusually warm overnight low temperatures add to heat stress into the next day?)

If those temperatures are at levels that pose an elevated risk for heat complications, such as heat stress, based on peer-reviewed science and heat-health thresholds supported by the Centers for Disease Control and Prevention (CDC) national data sets.

- National Weather Service