| Andrews, D. G., J. R. Holton, and C. B. Leovy, 1987: Middle Atmosphere Dynamics. Academic Press, 489 pp. |
| Baldwin, M. P., and T. J. Dunkerton, 2001: Stratospheric harbingers of anomalous weather regimes. Science, 294, 581−584, https://doi.org/10.1126/science.1063315. |
| Butler, A. H., J. P. Sjoberg, D. J. Seidel, and K. H. Rosenlof, 2017: A sudden stratospheric warming compendium. Earth System Science Data, 9, 63−76, https://doi.org/10.5194/essd-9-63-2017. |
| Charlton, A. J., and L. M. Polvani, 2007: A new look at stratospheric sudden warmings. Part I: Climatology and modeling benchmarks. J. Climate, 20, 449−469, https://doi.org/10.1175/JCLI3996.1. |
| Domeisen, D. I. V., and Coauthors, 2019: The role of the stratosphere in subseasonal to seasonal prediction Part I: Predictability of the stratosphere. J. Geophys. Res., https://doi.org/10.1029/2019JD030920. |
| Karpechko, A. Y., 2018: Predictability of sudden stratospheric warmings in the ECMWF extended-range forecast system. Mon. Wea. Rev., 146, 1063−1075, https://doi.org/10.1175/MWR-D-17-0317.1. |
| Karpechko, A. Y., P. Hitchcock, D. H. W. Peters, and A. Schneidereit, 2017: Predictability of downward propagation of major sudden stratospheric warmings. Quart. J. Roy. Meteorol. Soc., 143, 1459−1470, https://doi.org/10.1002/qj.3017. |
| Kobayashi, S., and Coauthors, 2015: The JRA-55 Reanalysis: General specifications and basic characteristics. J. Meteorol. Soc. Japan, 93, 5−48, https://doi.org/10.2151/jmsj.2015-001. |
| Lehtonen, I., and A. Y. Karpechko, 2016: Observed and modeled tropospheric cold anomalies associated with sudden stratospheric warmings. J. Geophys. Res., 121, 1591−1610, https://doi.org/10.1002/2015JD023860. |
| Rao, J., R. C. Ren, H. S. Chen, Y. Y. Yu, and Y. Zhou, 2018: The stratospheric sudden warming event in February 2018 and its prediction by a climate system model. J. Geophys. Res., 123, 13332−13345, https://doi.org/10.1029/2018JD028908. |
| Rao, J., R. C. Ren, H. S. Chen, X. W. Liu, Y. Y. Yu, J. G. Hu, and Y. Zhou, 2019a: Predictability of stratospheric sudden warmings in the Beijing Climate Center Forecast System with statistical error corrections. J. Geophys. Res., 124, 8385−8400, https://doi.org/10.1029/2019JD030900. |
| Rao, J., C. I. Garfinkel, H. S. Chen, and I. P. White, 2019b: The 2019 new year stratospheric sudden warming and its real-time predictions in multiple S2S models. J. Geophys. Res., 124, 11155−11174, https://doi.org/10.1029/2019JD030826. |
| Scaife, A. A., and Coauthors, 2016: Seasonal winter forecasts and the stratosphere. Atmospheric Science Letters, 17, 51−56, https://doi.org/10.1002/asl.598. |
| Seviour, W. J. M., D. M. Mitchell, and L. J. Gray, 2013: A practical method to identify displaced and split stratospheric polar vortex events. Geophys. Res. Lett., 40, 5268−5273, https://doi.org/10.1002/grl.50927. |
| Sigmond, M., J. F. Scinocca, V. V. Kharin, and T. G. Shepherd, 2013: Enhanced seasonal forecast skill following stratospheric sudden warmings. Nature Geoscience, 6, 98−102, https://doi.org/10.1038/ngeo1698. |
| Taguchi, M., 2014: Predictability of major stratospheric sudden warmings of the vortex split type: Case study of the 2002 Southern event and the 2009 and 1989 Northern events. J. Atmos. Sci., 71, 2886−2904, https://doi.org/10.1175/JAS-D-13-078.1. |
| Taguchi, M., 2016a: Predictability of major stratospheric sudden warmings: Analysis results from JMA operational 1-month ensemble predictions from 2001/02 to 2012/13. J. Atmos. Sci., 73, 789−806, https://doi.org/10.1175/JAS-D-15-0201.1. |
| Taguchi, M., 2016b: Connection of predictability of major stratospheric sudden warmings to polar vortex geometry. Atmospheric Science Letters, 17, 33−38, https://doi.org/10.1002/asl.595. |
| Taguchi, M., 2016c: Features of vortex split MSSWs that are problematic to forecast. Atmospheric Science Letters, 17, 517−522, https://doi.org/10.1002/asl.686. |
| Taguchi, M., 2018: Comparison of subseasonal-to-seasonal model forecasts for major stratospheric sudden warmings. J. Geophys. Res., 123, 10231−10247, https://doi.org/10.1029/2018JD028755. |
| Tripathi, O. P., A. Charlton-Perez, M. Sigmond, and F. Vitart, 2015a: Enhanced long-range forecast skill in boreal winter following stratospheric strong vortex conditions. Environmental Research Letters, 10, 104007, https://doi.org/10.1088/1748-9326/10/10/104007. |
| Tripathi, O. P., and Coauthors, 2015b: The predictability of the extratropical stratosphere on monthly time-scales and its impact on the skill of tropospheric forecasts. Quart. J. Roy. Meteorol. Soc., 141, 987−1003, https://doi.org/10.1002/qj.2432. |
| Vitart, F., and Coauthors, 2017: The Subseasonal to Seasonal (S2S) prediction project database. Bull. Amer. Meteorol. Soc., 98, 163−173, https://doi.org/10.1175/BAMS-D-16-0017.1. |
| Waugh, D. W., A. H. Sobel, and L. M. Polvani, 2017: What is the polar vortex and how does it influence weather? Bull. Amer. Meteorol. Soc., 98, 37−44, https://doi.org/10.1175/BAMS-D-15-00212.1. |