We thank three reviewers for their constructive and valuable comments. The ECMWF System 4 reforecasts were obtained by the authors through a commercial agreement between Georgia Tech and ECMWF. This research has been supported by NSF-AGS 0965610, NSF-ATM 0826909, and APEC Climate Center.
Berrisford, P., , D. Dee, , K. Fielding, , M. Fuentes, , P. Kallberg, , S. Kobayashi, , and S. Uppala, 2009: The ERA-Interim archive. ERA report series, No. 1, ECMWF, 16 pp. [Available online at ://www.ecmwf.int/publications/library/do/references/list/782009.]
Camargo, S. J., , A. G. Barnston, , P. J. Klotzbach, , and C. W. Landsea, 2007a: Seasonal tropical cyclone forecasts. WMO Bull., 56, 297–309.
Camargo, S. J., , A. W. Robertson, , S. J. Gaffney, , P. Smyth, , and M. Ghil, 2007b: Cluster analysis of typhoon tracks. Part II: Large-scale circulation and ENSO. J. Climate, 20, 3654–3676.
Chan, J. C. L., 2000: Tropical cyclone activity over the western North Pacific associated with El Niño and La Niña events. J. Climate, 13, 2960–2972.
Chan, J. C. L., 2008: Decadal variations of intense typhoon occurrence in the western North Pacific. Proc. Roy. Soc. London, A464, 249–272.
Chan, J. C. L., , J. Shi, , and C. M. Lam, 1998: Seasonal forecasting of tropical cyclone activity over the western North Pacific and the South China Sea. Wea. Forecasting, 13, 997–1004.
Chan, J. C. L., , J. Shi, , and C. M. Lam, 2001: Improvements in the seasonal forecasting of tropical cyclone activity over the western North Pacific. Wea. Forecasting, 16, 491–498.
Chen, T. C., , S. P. Weng, , N. Yamazaki, , and S. Kiehne, 1998: Interannual variation in the tropical cyclone activity over the western North Pacific. Mon. Wea. Rev., 126, 1080–1090.
Chen, T. C., , S. Y. Wang, , and M. C. Yen, 2006: Interannual variation of the tropical cyclone activity over the western North Pacific. J. Climate, 19, 5709–5720.
Chia, H. H., , and C. F. Ropelewski, 2002: The interannual variability in the genesis location of tropical cyclones in the northwest Pacific. J. Climate, 15, 2934–2944.
Gray, W. M., 1979: Hurricanes: Their formation, structure and likely role in the tropical circulation. Meteorology over the Tropical Oceans, D. B. Shaw, Ed., Royal Meteorological Society, 155–218.
Ho, C. H., , J. J. Baik, , J. H. Kim, , D. Y. Gong, , and C. H. Sui, 2004: Interdecadal changes in summertime typhoon tracks. J. Climate, 17, 1767–1776.
Ho, C. H., , J. H. Kim, , H. S. Kim, , C. H. Sui, , and D. Y. Gong, 2005: Possible influence of the Antarctic Oscillation on tropical cyclone activity in the western North Pacific. J. Geophys. Res., 110, D19104, doi:10.1029/2005JD005766.
Kim, H.-M., , and P. J. Webster, 2010: Extended-range seasonal hurricane forecasts for the North Atlantic with a hybrid dynamical-statistical model. Geophys. Res. Lett., 37, L21705, doi:10.1029/2010GL044792.
Kim, H.-M., , P. J. Webster, , and J. A. Curry, 2009: Impact of shifting patterns of Pacific Ocean warming on North Atlantic tropical cyclones. Science, 325, 77–80.
Kim, H.-M., , P. J. Webster, , and J. A. Curry, 2011: Modulation of North Pacific tropical cyclone activity by three phases of ENSO. J. Climate, 24, 1839–1849.
Kim, J.-H., , C.-H. Ho, , C.-H. Sui, , and S. K. Park, 2005: Dipole structure of interannual variations in summertime tropical cyclone activity over East Asia. J. Climate, 18, 5344–5356.
Knapp, K. R., , and M. C. Kruk, 2010: Quantifying interagency differences in tropical cyclone best-track wind speed estimates. Mon. Wea. Rev., 138, 1459–1473.
Knapp, K. R., , M. C. Kruk, , D. H. Levinson, , H. J. Diamond, , and C. J. Neumann, 2010: The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone data. Bull. Amer. Meteor. Soc., 91, 363–376.
Lea, A. S., , and M. A. Saunders, 2006: Seasonal prediction of typhoon activity in the Northwest Pacific basin. Preprints, 27th Conf. on Hurricanes and Tropical Meteorology, Monterey, CA, Amer. Meteor. Soc., P5.23. [Available online at https://ams.confex.com/ams/27Hurricanes/techprogram/paper_107641.htm.]
Liebmann, B., , H. H. Hendon, , and J. D. Glick, 1994: The relationship between tropical cyclones of the western Pacific and Indian Oceans and the Madden–Julian oscillation. J. Meteor. Soc. Japan, 72, 401–412.
Liu, K. S., , and J. C. L. Chan, 2003: Climatological characteristics and seasonal forecasting of tropical cyclones making landfall along the south China coast. Mon. Wea. Rev., 131, 1650–1662.
Liu, K. S., , and J. C. L. Chan, 2008: Interdecadal variability of western North Pacific tropical cyclone tracks. J. Climate, 21, 4464–4476.
Matsuura, T., , M. Yumoto, , and S. Iizuka, 2003: A mechanism of interdecadal variability of tropical cyclone activity over the western North Pacific. Climate Dyn., 21, 105–117.
Molteni, F., and Coauthors, 2011: The new ECMWF seasonal forecast system (System 4). ECMWF Tech. Memo. 656, 51 pp.
Reynolds, R. W., , N. A. Rayner, , T. M. Smith, , D. C. Stokes, , and W. Wang, 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15, 1609–1625.
Sobel, A. H., , and E. D. Maloney, 2000: Effect of ENSO and MJO on the western North Pacific tropical cyclones. Geophys. Res. Lett., 27, 1739–1742.
Stockdale, T. N., and Coauthors, 2011: ECMWF seasonal forecast system 3 and its prediction of sea surface temperature. Climate Dyn., 37, 455–471, doi:10.1007/s00382-010-0947-3.
Vecchi, G. A., , M. Zhao, , H. Wang, , G. Villarini, , A. Rosati, , A. Kumar, , I. M. Held, , and R. Gudgel, 2011: Statistical–dynamical predictions of seasonal North Atlantic hurricane activity. Mon. Wea. Rev., 139, 1070–1082.
Vitart, F., and Coauthors, 2007: Dynamically based seasonal forecasts of Atlantic tropical storm activity issued in June by EUROSIP. Geophys. Res. Lett., 34, L16815, doi:10.1029/2007GL030740.
Wang, B., , and J. C. L. Chan, 2002: How strong ENSO events affect tropical storm activity over the western North Pacific. J. Climate, 15, 1643–1658.
Wang, B., and Coauthors, 2009: Advance and prospectus of seasonal prediction: Assessment of the APCC/CliPAS 14-model ensemble retrospective seasonal prediction (1980–2004). Climate Dyn., 33, 93–117, doi:10.1007/s00382-008-0460-0.
Wang, H., , J.-K. E. Schemm, , A. Kumar, , W. Wang, , L. Long, , M. Chelliah, , G. D. Bell, , and P. Peng, 2009: A statistical forecast model for Atlantic seasonal hurricane activity based on the NCEP dynamical seasonal forecast. J. Climate, 22, 4481–4500.
Wu, M. C., , W. L. Chang, , and W. M. Leung, 2004: Impacts of El Niño–Southern Oscillation events on tropical cyclone landfalling activity in the western North Pacific. J. Climate, 17, 1419–1428.
Yeh, S. W., , S. K. Kang, , B. P. Kirtman, , J. H. Kim, , M. H. Kwon, , and C. H. Kim, 2010: Decadal change in relationship between western North Pacific tropical cyclone frequency and the tropical Pacific SST. Meteor. Atmos. Phys., 106, 179–189.