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 Jul-Aug-Sep 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 Aproduct A-Z list@.

U.S. Surface Climate Forecasts for Jul-Aug-Sep >96

Temperature: CCA predicts anomalous warmth in much of the East, eastern Midwest and Great Lakes, Texas, the Southwest, parts of the far West, and Hawaii. OCN forecasts warmth in Florida and the Southeast, the Mid-Atlantic, and small parts of the Pacific Northwest and the Southwest; and cold in the nation=s midsection. The coupled model dynamical forecast calls for warmth in Montana.

Precipitation: The OCN, CCA and the NCEP coupled model predict only small patches of positive and negative anomalies that show little agreement; thus no meaningful forecast is gleaned. CCA predicts above-median rainfall in the southern Hawaiian islands.

U.S. Surface Climate Forecasts for Jan-Feb-Mar >97

Temperature: CCA predicts anomalous warmth in the eastern half of the U.S. (Except Florida and Texas), central and northern Plains, and part of the west; and somewhat cool in all of Hawaii except for Maui. OCN forecasts warmth in most of the country, excluding the mid-section and the much of the central northern tier. The NCEP coupled model does not presently make forecasts this far in advance.

Precipitation: CCA predicts anomalous wetness in the southern half of Texas, in parts of the Gulf coast (including western Florida); and dryness along the northern tier especially from Montana to the Great Lakes. OCN predicts above median rainfall in the southern Rockies and southern Plains (Oklahoma, northern and central Texas) and Florida panhandle; dry in much of the Northwest and a 5-state region centered on the Ohio Valley. The NCEP coupled model does not presently make forecasts this far in advance.

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.

ENSO-Related SST

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 fall 1996, switching to a positive anomaly by late winter 1996-97. A warm episode is suggested during 1997. Specifically, the forecast calls for the following standardized anomalies and cross-validated correlation skills:

The forecast for Jul-Aug-Sep 1996 is a skill-weighted average of CCA and simple persistence of the anomaly observed in Mar-Apr-May, because persistence and CCA skills are roughly equivalent for that forecast. Longer lead forecasts reflect only CCA. The global field of SST anomaly for June 9-15, 1996 (Fig. 1) shows the currently near normal (cold) SST in the east-central (far 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, 1316­1345.

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 multi­season climate forecast system at the National Meteorological Center. Bull. Am. Meteor. Soc., 75, 569­577.

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, 929­948.

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.

Figures