PREDICTABILITY OF PRECIPITATION PATTERNS - AN OPERATIONAL APPROACH

Predictability, defined as the ability to forecast precipitation over an area by Lagrangian persistence, is studied for 11 radar precipitati on patterns. After a time ranging between 40 and 112 min, depending on individual cases, all forecast skill is lost. Attempts at relating th is range of predictability to larger-scale meteorological parameters l ead to positive results when the convective available potential energy is considered alone or in combination with wind shear energy. It appe ars from this study that the limited range of scales properly sampled by a single radar severely hampers the possibility of establishing a s olid empirical relationship between mesoscale predictability and synop tic-scale meteorological parameters.