Forecast Forum - June 2005

          The canonical correlation analysis (CCA) forecast of SST in the central Pacific (Barnett et al. 1988, Science, 241, 192‑196; Barnston and Ropelewski 1992, J. Climate, 5, 1316‑1345), is shown in Figs. F1 and F2. This forecast is produced routinely by the Prediction Branch of the Climate Prediction Center . The predictions from the National Centers for Environmental Prediction (NCEP) Coupled Forecast System Model (CFS03) are presented in Figs. F3 and F4a, F4b.  Predictions from the Markov model (Xue, et al. 2000: J. Climate, 13, 849‑871) are shown in Figs. F5 and F6.   Predictions from the latest version of the LDEO model (Chen et al. 2000: Geophys. Res. Let., 27, 2585‑2587) are shown in Figs. F7 and F8.  Predictions using linear inverse modeling (Penland and Magorian 1993: J. Climate, 6, 1067‑1076) are shown in Figs. F9 and F10. Predictions from the Scripps / Max Planck Institute (MPI) hybrid coupled model (Barnett et al. 1993: J. Climate, 6, 1545‑1566) are shown in Fig. F11.  Predictions from the ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633‑652) are shown in Fig. F12.  Ni�o 3.4 predictions are summarized in Fig. F13, provided by the Forecasting and Prediction Research Group of the IRI.

The CPC and the contributors to the Forecast Forum caution potential users of this predictive information that they can expect only modest skill.

Outlook

            ENSO-neutral conditions are expected during the next 3-6 months.

Discussion

Sea surface temperature (SST) anomalies increased throughout the eastern equatorial Pacific during June (Figs. T9 and T18, Table T2).  By the end of the month, positive equatorial SST anomalies were observed in most areas between Indonesia and 90�W, while negative anomalies persisted along the South American coast (Fig. T9).  

The increase in SST anomalies in the eastern equatorial Pacific during June was reflected in an increase in the departures in the Ni�o 3 and Ni�o 3.4 regions (Table T2, Fig. T5). The increase in SST anomalies in the eastern equatorial Pacific was consistent with weaker-than-normal low-level equatorial easterlies over the region (Fig. T20).  However, the overall pattern of tropical convection was near average (Fig. T25). During June there was very little week-to-week variation in circulation features, as the MJO became inactive (Figs. T11 and T12).

           Consistent with recent atmospheric and oceanic conditions, a majority of the statistical and coupled model forecasts (Figs. F1, F2, F3, F4a, F4b, F5, F6, F7, F8, F9, F10, F11, F12 and F13) indicate that SST anomalies will likely remain positive during the next 3-6 months, but still within the ENSO-neutral range.  Thus, it is most likely that ENSO-neutral conditions will continue during the remainder of the NH summer and fall.

           Weekly updates of SST, 850-hPa wind, OLR and features of the equatorial subsurface thermal structure are available on the Climate Prediction Center homepage at: http://www.cpc.ncep.noaa.gov/