Forecast Forum - March 2006

          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.  Niño 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

            La Niña conditions are expected to continue during the next 1-3 months.

Discussion

     The patterns of anomalous ocean temperatures, atmospheric circulation and precipitation are consistent in indicating La Niña conditions in the tropical Pacific. During March negative equatorial SST anomalies less than –0.5ºC were observed at most locations between 180ºW and 90ºW (Fig. T18), and negative SST departures were observed in all of the Niño regions, except for Niño 1+2 (Table T2 and Fig. T5). During the month, positive SST departures decreased in the extreme eastern equatorial Pacific (Fig. T9), as conditions returned to near average in that region (Fig. T25).

     During March above-average precipitation (negative OLR anomalies) was observed over Indonesia, the Philippines, northern Australia and Hawaii, while below-average precipitation (positive OLR anomalies) was observed over the central equatorial Pacific and over the eastern tropical Pacific between the equator and 10ºN (Fig. T25). Stronger-than-average low-level (850-hPa) easterly winds (Figs. T7 and T20) persisted over the central equatorial Pacific, and anomalous upper-level (200-hPa) cyclonic circulation centers were observed in both hemispheres (Fig. T22). The equatorial subsurface temperature anomaly pattern (negative anomalies in the central and eastern Pacific and positive anomalies in the western Pacific) persisted during February-March 2006 (Figs. T15 and T17), and the basin-wide upper ocean heat content, although increasing, remained below-average. These atmospheric and oceanic features are consistent with ongoing La Niña conditions.

       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/