FIGURE F12. Time series of predicted sea surface temperature anomalies (SSTA) for the Ni�o 4, Ni�o 3.4, Ni�o 3, and Ni�o 1+2 indices in �C and the Southern Oscillation Index (SOI) in standardized deviations based on the ENSO-CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633-652). The observed three-month average values are shown as a thick line. Three-month average forecast values are the thick line with horizontal bars, which indicate the adjusted RMSE. Anomalies are departures from the 1971�2000 base period for the SSTs and for the 1951�80 base period for the SOI.