Ropelewski, C. F. & Halpert, M. S. Global and regional scale precipitation patterns associated with the El Niño/Southern Oscillation. Mon. Weath. Rev. 115, 1606–1626 (1987).
Halpert, M. S. & Ropelewski, C. F. Surface temperature patterns associated with the Southern Oscillation. J. Clim. 5, 577–593 (1992).
Eichler, T. & Higgins, W. Climatology and ENSO-related variability of North American extratropical cyclone activity. J. Clim. 19, 2076–2093 (2006).
Lee, S-K., Mapes, B. E., Wang, C., Enfield, D. B. & Weaver, S. J. Springtime ENSO phase evolution and its relation to rainfall in the continental U.S. Geophys. Res. Lett. 41, 1673–1680 (2014).
Galway, J. G. Relationship between precipitation and tornado activity. Wat. Resour. Bull. 15, 961–964 (1979).
Rhomel, J. R., Niyogi, D. & Raman, S. Mesoclimatic analysis of severe weather and ENSO interactions in North Carolina. Geophys. Res. Lett. 27, 2269–2272 (2000).
Marzban, C. & Schaefer, J. T. The correlation between U.S. tornadoes and Pacific sea surface temperatures. Mon. Weath. Rev. 129, 884–895 (2001).
Cook, A. R. & Schaefer, J. T. The relation of El Niño–Southern Oscillation (ENSO) to winter tornado outbreaks. Mon. Weath. Rev. 136, 3121–3137 (2008).
Shepherd, M., Niyogi, D. & Mote, T. L. A seasonal-scale climatological analysis correlating spring tornadic activity with antecedent fall–winter drought in the southeastern United States. Environ. Res. Lett. 4, 024012 (2009).
Weaver, S. J., Baxter, S. & Kumar, A. Climatic role of North American low-level jets on US regional tornado activity. J. Clim. 25, 6666–6683 (2012).
Lee, S-K., Atlas, R., Enfield, D. B., Wang, C. & Liu, H. Is there an optimal ENSO pattern that enhances large-scale atmospheric processes conducive to major tornado outbreaks in the U.S.? J. Clim. 26, 1626–1642 (2013).
Verbout, S. M., Brooks, H. E., Leslie, L. M. & Schultz, D. M. Evolution of the U.S. tornado database: 1954–2003. Weath. Forecast. 21, 86–93 (2006).
Doswell, C. A. Small sample size and data quality issues illustrated using tornado occurrence data. Electron. J. Severe Storms Meteorol. 2, 1–16 (2007).
Tippett, M. K., Sobel, A. H. & Camargo, S. J. Association of U.S. tornado occurrence with monthly environmental parameters. Geophys. Res. Lett. 39, L02801 (2012).
Tippett, M. K., Sobel, A. H., Camargo, S. J. & Allen, J. T. An empirical relation between U.S. tornado activity and monthly environmental parameters. J. Clim. 27, 2983–2999 (2014).
Allen, J. T., Tippett, M. K. & Sobel, A. H. Associating monthly hail occurrence and large scale environment for the Continental United States. J. Adv. Model. Earth Syst. 7, http://dx.doi.org/10.1002/2014MS000397 (2015).
Barnston, A. G., Tippett, M. K., L’Heureux, M. L., Shuhua, L. & DeWitt, D. G. Skill of real-time seasonal ENSO model predictions during 2002–11: Is our capability increasing? Bull. Am. Meteorol. Soc. 93, 631–651 (2012).
Barrett, B. S. & Gensini, V. A. Variability of central United States April–May tornado day likelihood by phase of the Madden–Julian Oscillation. Geophys. Res. Lett. 40, 2790–2795 (2013).
Munich RE, Severe Weather in North America Munich RE Report Number 302-07563, 274 (Munich RE, 2013).
Brooks, H. E., Lee, J. W. & Craven, J. P. The spatial distribution of severe thunderstorm and tornado environments from global reanalysis data. Atmos. Res. 68, 73–94 (2003).
Gensini, V. A. & Ashley, W. S. Climatology of potentially severe convective environments from North American regional reanalysis. Electron. J. Severe Storms Meteorol. 6, 1–40 (2011).
Allen, J. T. & Karoly, D. J. A climatology of Australian severe thunderstorm environments 1979–2011: Inter-annual variability and ENSO influence. Int. J. Climatol. 34, 81–97 (2014).
Diffenbaugh, N. S., Scherer, M. & Trapp, R. J. Robust increases in severe thunderstorm environments in response to greenhouse forcing. Proc. Natl Acad. Sci. USA 110, 16361–16366 (2013).
Tippett, M. K., Allen, J. T., Gensini, V. A. & Brooks, H. E. Climate and hazardous convective weather. Curr. Clim. Change Rep. (in the press, 2014).
Karl, T. R. & Koss, W. J. Regional and National Monthly, Seasonal, and Annual Temperature Weighted by Area, 1895–1983 38 (Historical Climatology Series 4-3, National Climatic Data Center, 1984).
Climate Prediction Center. Changes to the Oceanic Niño Index (2014); http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
Wilks, D. S. Extending logistic regression to provide full-probability-distribution MOS forecasts. Meteorol. Appl. 16, 361–368 (2009).
Schaefer, J. T. & Edwards, R. The SPC tornado/severe thunderstorm database. Am. Meteorol. Soc.215–220 (1999).
Mesinger, F. et al. North American regional reanalysis. Bull. Am. Meteorol. Soc. 87, 343–360 (2006).
Epstein, E. S. A scoring system for probability forecasts of ranked categories. J. Appl. Meteorol. 8, 985–987 (1969).