Wet-Bulb Globe Temperature Forecasts as an Aid to Decision-Makers in the Assessment of Heat Risk

Historically, National Weather Service (NWS) meteorologists have primarily utilized the Heat Index (HI) parameter for determining the necessity of heat advisories and warnings. HI has been a relatively adequate means of assessing heat impacts on sedentary populations, but recent morbidity research proves its shortcomings capturing the heat risk for active individuals.

The Wet Bulb Globe Temperature (WBGT) is a composite parameter that estimates the combined effects of temperature, humidity, wind, and solar radiation on humans, and has been found to be a more effective means of assessing exertional heat illness (EHI).

Furthermore, WBGT is a common heat metric used in athletic, occupational, and military settings to determine activity modifications and safety limits for physical activity during extreme heat. However, due to the absence of consistent, national, fine-scale WBGT forecast data, inability to comply with the existing activity modification guidelines is a major challenge for many decision-makers.

In addition to the NWS’s provision of HI forecasts, recent efforts have been made to provide forecasts for WBGT as an experimental element in the National Digital Forecast Database (NDFD). An update on where the project stands will be provided, along with a look at how WBGT forecasts can support the various needs of WBGT users.