result make preventable errors in the decision process. More sophisticated users of weather and climate information, particularly those in the commercial markets, usually do take uncertainty into consideration in the decision-making process. These users generally receive products and services from the meteorological community that highlight and, in many cases, quantify uncertainty associated with a forecast. However, in the general public market there are occasions when improper statements or lack of explanations of uncertainty can result in inadequate or inappropriate action or missed opportunities. These actions range from the public not taking necessary precautions in a life-threatening severe weather situation to governments and businesses missing opportunities to respond to or mitigate potential long-term impacts of climate variability and change.

As sources for weather and climate information have increased, especially given the many sources of information now available on the Web, the issue of confidence in the information has become more important. Communication of accuracy, reliability, and forecaster confidence is made even more complex when issues of climate forecasting are added to the mix.


Recent history provides a rich record of case studies that can be used to describe the strengths and weaknesses in the communication of weather and climate information to decision makers. This workshop explored five cases representing a range of time scales and issues. They address the forecasting of weather events, seasonal outlooks, and projections of climate change, and include cases in which the forecasts were of high quality and cases in which the forecasts or projections were of uncertain or unknown quality. In each case the impacts were largely dependent on the way the information was communicated. In particular, the workshop focused on the issue of communicating uncertainties. The cases presented are as follows:

Red River of the North Flood, Grand Forks, April 1997 (presented by Lee Anderson, Susan Avery, and Roger Pielke, Jr.). This major, record-breaking flood, its forecasts, and the public response illustrate the need for complete information, including a well-defined understanding of uncertainties by the emergency management community.

East Coast Winter Storm, March 2001 (presented by Raymond Ban, George Frederick, James Hoke, and Robert Ryan). This case looks at the complicated relationships that link the forecasting community, the media, the public, and decision makers. It also examines the competitive pressures faced by the media when a forecast of a major storm is a headline news story. The case shows how a forecast can be successful from a technical perspective (i.e., provides a relatively sound forecast) but have its usefulness compromised by problems communicat-

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