1. Providing Weather Forecast Uncertainty Information to the Public Julie Demuth, Rebecca Morss, & Jeff Lazo NCAR Societal Impacts Program USWRP AMS Summer Community Meeting, Boulder, CO August 11, 2008 AMS Summer Community Meeting, Boulder, CO August 11, 2008

2. The forecast high temperature for Boulder tomorrow is 88ºF. a) 88ºF b) 87-89ºF c) 86-90ºF d) 83-93ºF e) 78-98ºF What do you think the actual high temp will be?

3. Methodology Nationwide controlled-access web survey of public Analysis based on N=1465 completed responses Uncertainty-related research questions: How much confidence do people have in different types of weather forecasts? Do people infer uncertainty into deterministic forecasts and, if so, how much? How do people interpret a type of uncertainty forecast that is already commonly available and familiar: PoP? To what extent do people prefer to receive forecasts that are deterministic versus those that express uncertainty? What formats do people prefer for receiving forecast uncertainty information?

4. Suppose the forecast high temperature for tomorrow for your area is 75°F. What do you think the actual high temperature will be? 0% 10% 20% 30% 40% 50% 75°F74-76°F (± 1°F) 73-77°F (± 2°F) 70-80°F (± 5°F) 65-85°F (± 10°F) Other Percent of Respondents N=1465

5. 0%10%20%30%40%50% Prefer Channel A (deterministic) Prefer Channel B (uncertainty) Like both channels Like neither channel I don't know Percent of Respondents Suppose you are watching the local evening news … The Channel A weather forecaster says the high temperature will be 76°F tomorrow The Channel B weather forecaster says the high temperature will be between 74°F and 78°F tomorrow. N=1465

6. Broader implications Interest in providing uncertainty information… …but limited understanding of how to do this Empirical knowledge about what weather forecast information people get, want, use, etc. is critical Provide people information that they actually want and use rather than what we think they do (or should) want and use So much from social sciences (ideas, methodologies, theoretical frameworks, etc.) to integrate!