Planning outdoor events in the summer inevitably entails consulting weather reports. Did you hope to go to the beach for the day? Think again! Al Roker just told you there is a 90 percent chance of thunderstorms. While checking the forecast can be helpful, we often agonize over decisions because of weather reports: should you cancel the high school graduation party planned months in advance when there is a 70 percent chance of strong storms? How about 60 percent? [...]