The author would like to acknowledge extensive discussions with Dr. Tim DelSole. This work was supported by the National Science Foundation under Grant ATM-03-32910, the National Aeronautics and Space Administration under Grant NNG-04-GG46G, and the National Oceanic and Atmospheric Administration under Grant NA04-OAR-4310034.
Arnott, J. M., , J. L. Evans, , and R. Chiaromonte, 2004: Characterization of extratropical transition using cluster analysis. Mon. Wea. Rev., 132 , 2916–2937.
Blackmon, M. L., 1976: A climatological spectral study of the 500 mb geopotential height of the Northern Hemisphere. J. Atmos. Sci., 33 , 1607–1623.
Bretherton, C. S., , C. Smith, , and J. M. Wallace, 1992: Comparison of methods for finding coupled patterns in climate data. J. Climate, 5 , 541–560.
Christiansen, B., 2005: The shortcomings of nonlinear principal component analysis in identifying circulation regimes. J. Climate, 18 , 4815–4832.
Michelangeli, P-A., , R. Vautard, , and B. Legras, 1995: Weather regimes: Recurrence and quasi stationarity. J. Atmos. Sci., 52 , 1237–1256.
Monahan, A. H., , L. Pandolfo, , and G. Flato, 2001: The preferred structure of variability of the northern hemisphere atmospheric circulation. Geophys. Res. Lett., 28 , 1019–1028.
Nakamura, H., , and J. M. Wallace, 1990: Observed changes in baroclinic wave activity during the life cycles of low-frequency circulation anomalies. J. Atmos. Sci., 47 , 1100–1116.
Nakamura, H., , M. Nakamura, , and J. L. Anderson, 1997: The role of high- and low-frequency dynamics in blocking formation. Mon. Wea. Rev., 125 , 2074–2093.
Reinhold, B. B., , and R. T. Pierrehumbert, 1982: Dynamics of weather regimes: Quasi-stationary waves and blocking. Mon. Wea. Rev., 110 , 1105–1145.
Smyth, P., , K. Ide, , and M. Ghil, 1999: Multiple regimes in Northern-Hemisphere height fields via mixture model clustering. J. Atmos. Sci., 56 , 3704–3723.
Straus, D. M., , S. Corti, , and F. Molteni, 2007: Circulation regimes: Chaotic variability versus SST-forced predictability. J. Climate, 20 , 2251–2272.
Vautard, R., , and B. Legras, 1988: On the source of midlatitude low-frequency variability. Part II: Nonlinear equilibration of weather regimes. J. Atmos. Sci., 45 , 2845–2867.
Wallace, J. M., , C. Smith, , and C. S. Bretherton, 1992: Singular value decomposition of wintertime sea surface temperature and 500-mb height anomalies. J. Climate, 5 , 561–576.