Because the CCA (Barnston 1994) and OCN (Huang et al. 1995) methods are now being used for the official operational long-lead seasonal forecasts issued by the Climate Prediction Center of NCEP, they will no longer be presented in detail in this Experimental Forecast Bulletin. However, a brief summary of these forecasts, as well as that of the NCEP coupled model (Ji et al. 1994a,b), for Oct-Nov-Dec 1996 and Jan-Feb-Mar 1997 is provided. For further information about the official NCEP forecasts, the following U.S. Regional Climate Center (RCC) Offices may be contacted:

   Northeastern RCC      607-255-5950
   Southeastern RCC      803-737-0800
   Southern RCC          504-388-5021
   Midwest RCC           217-244-8226
   High Plains RCC       402-472-8294
   Western RCC           702-677-3106

The forecasts themselves are contained in the Climate Outlook, available on Internet with address: http://nic.fb4.noaa.gov. That same address can also be used to access the web site for this Bulletin, as follows: http://nic.fb4.noaa.gov/products/predictions; then click on "product A-Z list".

Temperature: OCN forecasts anomalous cold in the midsection of the country, warm in south Florida. CCA predicts cold in western Alaska, warm in Hawaii. The coupled model dynamical forecast does not call for any coherent large scale anomaly patterns in the U.S.

Precipitation: CCA predicts dryness in western Alaska. OCN predicts wetness in much of the country's midsection and parts of Midwest. The coupled model dynamical forecast does not call for any large scale anomaly patterns in the U.S.

Temperature: CCA predicts anomalous warmth in the eastern U.S.--especially the Great Lakes/Midwest, cool in 2 northern Hawaiian islands. OCN forecasts warmth along eastern seaboard (except Florida), Texas and the Southwest. The NCEP coupled model calls for below normal in Florida, the Great Lakes and Maine.

Precipitation: CCA predicts anomalous dryness around the Great Lakes. OCN predicts above median rainfall in parts of the Southwest and in the Florida panhandle. The NCEP coupled model predicts anomalous dryness in most of Florida.

Note: The above forecast descriptions include only regions whose estimated cross-validated correlation skill exceeds 0.3. Highest local skills are usually in the neighborhood of 0.6, but this varies with season, lead time and forecast tool.

CCA (Barnston and Ropelewski 1992, Smith et al. 1995) predicts slightly below normal SST conditions in Nino 3.4 (120-170^oW, 5 ^oN-5 ^oS) through early winter 1996-97, switching to a weak positive anomaly by late winter and becoming a warm episode (with low forecast confidence) during 1997. Specifically, the forecast calls for the following standardized anomalies and cross-validated correlation skills:

The forecast for Oct-Nov-Dec 1996 is a skill-weighted average of CCA and simple persistence of the anomaly observed in Jun-Jul-Aug, because persistence and CCA skills are roughly equivalent for that forecast. Longer lead forecasts reflect only CCA. The global field of SST anomaly for September 8-14, 1996 (Fig. 1) shows the currently still slightly below normal SST in parts of the eastern equatorial Pacific.

Barnston, A.G., 1994: Linear statistical short-term climate predictive skill in the Northern Hemisphere. J. Climate, 5, 1514-1564.

Barnston, A.G. and C.F. Ropelewski, 1992: Prediction of ENSO episodes using canonical correlation analysis. J. Climate, 7, 1316-1345.

Huang, J., H.M. van den Dool and A.G. Barnston, 1996: Long-lead seasonal temperature prediction using optimal climate normals. J. Climate, 9, 809-817.

Ji, M., A. Kumar and A. Leetmaa, 1994a: A multi-season climate forecast system at the National Meteorological Center. Bull. Am. Meteor. Soc., 75, 569-577.

Ji, M., A. Kumar and A. Leetmaa, 1994b: An experimental coupled forecast system at the National Meteorological Center: Some early results. Tellus, 46A, 398-418.

Reynolds, R.W. and T.M. Smith, 1994: Improved global sea surface temperature analysis using optimum interpolation. J. Climate, 7, 929-948.

Smith, T.M., A.G. Barnston, M. Ji and M. Chelliah, 1995: The impact of Pacific Ocean subsurface data on operational prediction of tropical Pacific SST at the NCEP. Wea. Forecasting, 10, 708-714.

Fig. 1. NCEP optimum interpolation (OI; Reynolds and Smith 1994) global SST anomaly field for the week of September 8-14, 1996.