The Use of Credible Intervals in Temperature Forecasting: Some Experimental Results

Abstract

Since 1965, the National Weather Service (NWS) in the United States has routinely issued precipitation probability forecasts to the general public. Forecasts of maximum and minimum temperature, however, are still expressed in categorical terms. NWS forecasts usually give point forecasts when forecasting temperature (e. g., “the high temperature tomorrow will be 75°F”), and such forecasts do not provide any information about the uncertainty inherent in the forecasts. Point forecasts are sometimes replaced by interval forecasts (e. g., “the high temperature tomorrow will be between 73°F and 77°F”), but such forecasts only provide a very informal representation of the forecaster’s uncertainty. The potential user of the forecast does not know whether the forecaster is almost certain that the high temperature will fall in the forecast interval or whether the forecaster feels, say, that there is only a 50-50 chance that the high temperature will fall in the forecast interval.

Notes

Supported in part by the National Science Foundation under Grants GA-31735 and GA-41232

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

On occasion, other duties prevented the forecasters from making these forecasts. However, we are confident that these occasions were not related to the difficulty of the respective forecasting situations.