National Weather Service Extreme Heat Products and Services Evolution

Heat continues to be the leading weather-related killer with the Centers for Disease Control and Prevention (CDC) estimating more than 700 deaths and 2,800 hospitalizations a year resulting from heat exposure. NOAA's global analysis shows that the ten warmest years on record have all occurred since 2005, and seven of the ten have occurred just since 2014. Not only are heat waves occurring more frequently, but are also more intense and longer-lasting with less cooling overnight, leading to more strain on the human body.

The National Weather Service (NWS) continues to develop and improve its heat services including tools to determine heat stress and methodologies for communicating and messaging the threat of heat. In this presentation, we will review the current and new tools being used - Heat Index, Wet-Bulb Globe Temperature (WBGT), and the CONUS-wide expansion of HeatRisk - and the challenges communicating the impacts of extreme heat. These tools can be used alongside the Hazardous Weather Outlook (HWO) and Graphical HWO to message dangerous heat. To further amplify the messaging around heat, the Climate Prediction Center (CPC) and Weather Prediction Center (WPC) are now coordinating to produce Extreme Heat Key Messages to highlight the agency’s most essential information for upcoming and/or occurring extreme temperatures when they are expected to be high-impact events affecting a broad area and are significantly anomalous.

The NWS has been focused on simplification of its Watch, Warning, and Advisory (WWA) system to alert users of various weather and water-based hazards. To address user confusion, NWS has been working to simplify messaging for the benefit of the Nation. As part of this initiative, the NWS will be renaming Excessive Heat Watch/Warning to Extreme Heat Watch/Warning, with a current expected implementation date of Spring 2025.

As heat impacts can be greatly individualized, NWS works within the National Integrated Heat Health Information System (NIHHIS) to build a greater understanding and partnerships with federal health partners such as CDC, U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, and Occupational Safety and Health Administration.