The three dimensions of prediction and service

Spatial precision, temporal precision and lead time are properties of any prediction and are also measures of the service provided. Together these three quantities describe the precision required to locate an event successfully in the three forecast dimensions. Failure to locate the event with the precision required is an incorrect forecast. The values of these quantities are determined by the requirements of the clients as well as the capabilities of the science.

A proposed design for an updated Severe Weather Program in the Meteorological Service of Canada (MSC) explicitly considers the three forecast dimensions. The resulting performance measurement is a three dimensional surface for a specific lead time. The shape and slope of the performance measurement surface reveals the skill of the program at various spatial and temporal precisions. The volume under the surface is a one number summary of the program skill integrated over all spatial and temporal scales.