Modifying The Extended Forecast Graphic To Improve Comprehension

The extended forecast graphic (EFG) is a popular graphic used by meteorologists to convey weather information, but it is poorly understood by the public. Deficiencies in the format, content, and presentation of the EFG contribute to a decrease in the efficacy of this graphic and reduce the comprehension of weather information. The format of the EFG has largely gone unchanged since the graphic first became popular more than four decades ago. The goal of this research was to modify the format of the existing EFG to address current limitations that inhibit understanding and create confusion among the public. Data were gathered from an online survey of the public (n = 885). Four modified versions of the EFG were developed, evaluated, and compared with the existing EFG. Removing probability of precipitation (PoP) information, reducing the number of days shown, and switching to a horizontal layout featuring timing and intensity information resulted in higher percentages for comprehension of weather information and positive comments when compared with the current version. A majority of participants responded that forecasters could accurately predict the weather 3 days out, providing justification for the reduction in number of days shown in the modified EFGs. Results suggest that agencies and members of the meteorological community should continue evaluating and discussing the most effective ways to use graphics to convey weather information to their audiences. Significance StatementThe extended forecast graphic is used by broadcast and government meteorologists to show forecast data and trends beyond 3 days. Although widely used, the graphic has proven to be confusing to the public. We experiment with various design and content changes in the graphic to reduce confusion caused by existing flaws in the current format of the graphic. We find that reducing the number of days to three and removing probabilities of precipitation to include more specific information improved comprehension. This finding is especially relevant given that existing extended forecast graphics almost always include probabilities of precipitation and increasingly are showing 10 or more days. Future studies should work to uncover other possible flaws in popular weather graphics.