Evolution of National Weather Service Extreme Temperature Tools, Messaging, and NIHHIS Collaboration

Extreme temperature is the leading weather-related killer on either end of the spectrum: heat and cold. The Centers for Disease Control and Prevention (CDC) estimates more than 1,200 deaths and 9,000 hospitalizations a year resulting from heat exposure. The National Oceanic and Atmospheric Administration's (NOAA) global analysis shows that the last 10 years have been the 10 warmest years on record. 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. Vulnerability to extreme temperatures is not just related to heat. Vulnerability to cold depends on factors such as socioeconomic status, age, and baseline health. The CDC states that while deaths and injuries related to extreme cold events are projected to decline due to warming climate, these reductions are not expected to compensate for the increase in heat-related deaths.

The National Weather Service (NWS) has been focused on simplifying its Watch, Warning, and Advisory (WWA) system through the NWS Hazard Simplification project. As part of this effort, the NWS will rename Excessive Heat Watch/Warning to Extreme Heat Watch/Warning, consolidate Wind Chill Watch/Warning into Extreme Cold Watch/Warning, rename Wind Chill Advisory to Cold Weather Advisory, and consolidate Hard Freeze Watch/Warning into Freeze Watch/Warning.

The consolidation of the Wind Chill and Extreme Cold products will help to clarify that cold can be dangerous with or without wind. Additionally, NWS will be consolidating Freeze and Hard Freeze watch/warning products to simplify messaging of cold conditions during the growing season that may be harmful to vegetation.

To better communicate the danger of heat, NWS recently transitioned its HeatRisk Prototype to Experimental status and expanded it across the contiguous United States. Experimental HeatRisk leverages generalized heat-health science with local climatology and heat-health statistics to produce a daily value of expected heat risk for each 24-hour period within any upcoming 7-day forecast period. It represents a new approach to providing daily heat risk information in an easy to view format using a nationally consistent methodology. Additionally, NWS completed a social science study earlier this year that was focused on the perceptions of heat risk with focus groups and 1,000 members of the general public. The results from this study will inform heat danger communications guidelines for NWS to strengthen our heat services and more effectively message the impacts of heat.

It is recognized that these efforts cannot be done alone, and it is imperative that the Weather, Water, Climate Enterprise work in alignment with the public health community to address these growing challenges. As a co-lead of NIHHIS, the NWS works with over 24 different federal agencies, including CDC, U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, and Occupational Safety and Health Administration, to identify and address gaps in heat and heat-health related information, research, safety, and resources. NIHHIS has been focused on developing a Federal Heat Communications Plan - which captures federal agencies’ planned activities in 2024 for messaging heat safety, tools and resources - and the Federal Heat Strategic Plan, which will lay out the direction for federal heat coordination and collaboration through 2030.