This replaces simple persistence as a skill threshold. Multiple least squares regression is employed to test a total of fourteen possible predictors for the selection of the bestpredictors, based upon 1950-1994 developmental data. A range of zero to four predictors were chosen in developing twelve separate regression models, developed separately for each initial calendar month.
Predictors are the predictands themselves at earlier times.
Final skill estimates reflect levels comparable to those of more sophisticated statistical and dynamical models. Results for the SSTs in Nino 3.4 and Nino 3 as well as the SOI are shown in Fig.1. These forecasts indicate that mild La Nina to neutral may continue through early spring of 2001, but there are large regional differences in the evolution of SST anomalies. All regions show warming from summer 2001 to winter 2001-2002. The forecast of conditions in Nino 3 produces a similar warming, but SST anomalies remain negative or neutral through next winter.