S2S Research Supported by California Department of Water Resources

Luna-Niño, R., Gershunov, A., Ralph, F.M. Weyant, A., Guirguis, K., DeFlorio, M.J., Cayan D.R., & Williams, A.P. (2025). Heresy in ENSO teleconnections: atmospheric rivers as disruptors of canonical seasonal precipitation anomalies in the Southwestern US. Climate Dynamics, 63, 115. https://doi.org/10.1007/s00382-025-07583-1

Sengupta, A., Waliser, D.E., DeFlorio, M.J. et al. Role of evolving sea surface temperature modes of variability in improving seasonal precipitation forecasts. Commun Earth Environ6, 256 (2025). https://doi.org/10.1038/s43247-025-02235-y

Wang, J., Domeisen, D. I. V., Garfinkel, C. I., Jenney, A. M., Kim, H., Wu, Z., Zheng, C., & Stan, C. (2025). The potential impacts of improved MJO prediction on the prediction of MJO teleconnections in the UFS global fully coupled model. Climate Dynamics, 63, 312. https://doi.org/10.1007/s00382-025-07783-9

DeFlorio, M. J., and Coauthors, 2024: From California’s Extreme Drought to Major Flooding: Evaluating and Synthesizing Experimental Seasonal and Subseasonal Forecasts of Landfalling Atmospheric River and Extreme Precipitation during Winter 2022/23. Bull. Amer. Meteor. Soc., 105, E84E104, https://doi.org/10.1175/BAMS-D-22-0208.1.

Guirguis, K., Hatchett, B., Gershunov, A., DeFlorio, M., Clemesha, R., Brandt, W. T., Haleakala, K., Castellano, C. Niño, R. L., Tardy, A., Anderson, M., & Ralph, F. M. (2024). Reinterpreting ENSO's role in modulating impactful precipitation events in California. Geophysical Research Letters, 51(14), e2024GL110326. https://doi.org/10.1029/2024GL110326

Higgins, T. B., Subramanian, A. C., Chapman, W. E., Lavers, D. A., & Winters, A. C. (2024). Subseasonal Potential Predictability of Horizontal Water Vapor Transport and Precipitation Extremes in the North Pacific. Weather and Forecasting, 39(6), 833-846. https://doi.org/10.1175/WAF-D-23-0170.1

Scheftic, W. D., Zeng, X., Brunke, M. A., DeFlorio, M. J., Ouyed, A., & Sanden, E. (2024). On the use of hindcast skill for merging NMME seasonal forecasts across the western U.S. Weather and Forecasting, 39(12), 1907–1917. https://doi.org/10.1175/WAF-D-24-0070.1

Wang, J., DeFlorio, M. J., Gershunov, A., Guirguis, K., Delle Monache, L., & Ralph, F. M. (2024). Association of western US compound hydrometeorological extremes with Madden-Julian oscillation and ENSO interaction. Communications Earth & Environment, 5, 314. https://doi.org/10.1038/s43247-024-01449-w

Castellano, C. M., DeFlorio, M. J., Gibson, P. B., Delle Monache, L., Kalansky, J. F., Wang, J., et al. (2023). Development of a statistical subseasonal forecast tool to predict California atmospheric rivers and precipitation based on MJO and QBO activity. Journal of Geophysical Research: Atmospheres, 128, e2022JD037360. https://doi.org/10.1029/2022JD037360

Dong, C., Y. Peings and G. Magnusdottir, 2023: Regulation of southwestern United States precipitation by non-ENSO teleconnections and the impact of the background flow. J. Climate. https://doi.org/10.1175/JCLI-D-23-0081.1

Guirguis, K., Gershunov, A., Hatchett, B. J., DeFlorio, M. J., Subramanian, A. C., Clemesha, R., Delle Monache, L., & Ralph, F. M. (2023). Subseasonal prediction of impactful California winter weather in a hybrid dynamical-statistical framework. Geophysical Research Letters, 50, e2023GL105360. https://doi.org/10.1029/2023GL105‍ ‍

Scheftic, W. D., Zeng, X., & Brunke, M. A. (2023). Seasonal forecasting of precipitation, temperature, and snow mass over the western U.S. by combining ensemble post-processing with empirical oceanatmosphere teleconnections. Weather and Forecasting. https://doi.org/10.1175/WAF-D-22-0099.1‍ ‍

Su, L., Q. Cao, S. Shukla, M. Pan, and D. P. Lettenmaier (2023), Evaluation of subseasonal drought forecast skill over the coastal Western U.S. Journal of Hydrometeorology, https://doi.org/10.1175/JHMD-22-0103.1.

Wang, J., M. J. DeFlorio, B. Guan, and C. M. Castellano (2023), Seasonality of MJO impacts on precipitation extremes over the western U.S. Journal of Hydrometeorology, 24, 151166. https://doi.org/10.1175/JHM-D-22-0089.1.

Zhang, Z., M. J. DeFlorio, L. Delle Monache, A. C. Subramanian, F. M. Ralph, D. E. Waliser, M. Zheng, B. Guan, A. Goodman, A. Molod, F. Vitart, A. Kumar, and H. Lin (2023), Multi-model subseasonal forecast skill assessment of water vapor transport associated with atmospheric rivers over the U.S. west coast. Journal of Geophysical Research – Atmospheres. https://doi.org/10.1029/2022JD037608

Jiang, X., D. E. Waliser, P. B. Gibson, G. Chen, and W. Guan (2022), Why seasonal prediction of California winter precipitation is challenging. Bulletin of the American Meteorological Society, 103(12), E2688E2700. https://doi.org/10.1175/BAMS-D-21-0252.1

Peings, Y., Y. Lim, G. Magnusdottir, 2022: Potential predictability of southwest US rainfall: Role of tropical and high-latitude variability. J. Climate. https://doi.org/10.1175/JCLI-D-21-0775.1

Sengupta, A., B. Singh, M. J. DeFlorio, C. Raymond, A. W. Robertson, X. Zeng, D. E. Waliser, and J. Jones (2022), Advances in sub-seasonal to seasonal prediction relevant to water management in the western United States. Bulletin of the American Meteorological Society, 103, E2168-E2175. https://doi.org/10.1175/BAMS-D-22-0146.1.

Coelho, M. J. DeFlorio, L. Delle Monache, F. Di Giuseppe, A. M. García-Solórzano, P. B. Gibson, L. Goddard, C. González-Romero, R. J. Graham, R. M. Graham, C. M. Grams, A. Halford, W. T. K. Huang, K. Jensen, M. Kilavi, K. A. Lawal, R. W. Lee, D. MacLeod, A. Manrique-Suñén, E. S. P. R. Martins, C. J. Maxwell, W. J. Merryfield, A. G. Muñoz, E. Olaniyan, G. Otieno, J. A. Oyedepo, L. Palma, I. G. Pechlivanidis, D. Pons, F. M. Ralph, D. S. Reis Jr., T. A. Remenyi, J. S. Risbey, D. J. C. Robertson, A. W. Robertson, S. Smith, A. Soret, T. Sun, M. C. Todd, C. R. Tozer, F. C. Vasconelos Jr., I. Vigo, D. E. Waliser, F. Wetterhall, and R. G. Wilson (2022), Advances in the application and utility of subseasonal-to-seasonal predictions. Bulletin of the American Meteorological Society, 1(aop), 1-57. https://doi.org/10.1175/BAMS-D-20-0224.1.

Cao, Q., S. Shukla, M. J. DeFlorio, F. M. Ralph, and D. P. Lettenmaier (2021), Evaluation of the subseasonal forecast skill of floods associated with atmospheric rivers in coastal Western U.S. watersheds. Journal of Hydrometeorology, https://doi.org/10.1175/JHM-D-20-0219.1.

DeFlorio, M. J., F. M. Ralph, D. E. Waliser, J. Jones, and M. L. Anderson (2021), Better subseasonal-toseasonal forecasts for water management. EOS, 102, https://doi.org/10.1029/2021EO159749.

Gibson, P. B., W. E. Chapman, A. Altinok, L. Delle Monache, M. J. DeFlorio, and D. E. Waliser (2021), Training machine learning models on climate model output yields skillful interpretable seasonal precipitationforecasts. Nature Communications Earth & Environment, 2, 159. https://doi.org/10.1038/s43247-021-00225-4.

Lim, Y., Y. Peings and G. Magnusdottir, 2021: The role of atmospheric drivers in a sudden transition of California precipitation in the 2012/13 winter. Journal of Geophys. Research Atmospheres, 126, e2021JD035028. https://doi.org/10.1029/2021JD035028

Gibson, P. B., D. E. Waliser, B. Guan, M. J. DeFlorio, F. M. Ralph, and D. L. Swain (2020a), Ridging associated with drought in the Western and Southwestern United States: characteristics, trends, and predictability sources. Journal of Climate, 33, 2485-2508. https://doi.org/10.1175/JCLI-D-19-0439.1.

Gibson, P. B., D. E. Waliser, A. Goodman, M. J. DeFlorio, L. Delle Monache, and A. Molod (2020b), Subseasonal-to-seasonal hindcast skill assessment of ridging events related to drought over the Western United States. Journal of Geophysical Research - Atmospheres, 125, e2020JD033655. https://doi.org/10.1029/2020JD033655.

Guirguis, K., A. Gershunov, M. J. DeFlorio, T. Shulgina, L. Delle Monache, A. C. Subramanian, T. W. Corringham, and F. M. Ralph (2020), Four atmospheric circulation regimes over the North Pacific and their relationship to California precipitation on daily to seasonal timescales. Geophysical Research Letters, 47, e2020GL087609. https://doi.org/10.1029/2020GL087609.

Merryfield, W. J., J. Baehr, L. Batté, E. J. Becker, A. H. Butler, C. A. S. Coelho, G. Danabasoglu, P. A. Dirmeyer, F. J. Doblas-Reyes, D. I. V. Domeisen, L. Ferranti, T. Ilynia, A. Kumar, W. A. Müller, M. Rixen, A. W. Robertson, D. M. Smith, Y. Takaya, M. Tuma, F. Vitart, C. J. White, M. S. Alvarez, C. Ardilouze, H. Attard, C. Baggett, M. A. Balmaseda, A. F. Beraki, P. S. Bhattacharjee, R. Bilbao, F. M. de Andrade, M. J. DeFlorio, L. B. Díaz, M. A. Ehsan, G. Fragkoulidis, S. Grainger, B. W. Green, M. C. Hell, J. M. Infanti, K. Isensee, T. Kataoka, B. P. Kirtman, N. P. Klingaman, J.-Yi Lee, K. Mayer, R. McKay, J. V. Mecking, D. E. Miller, N. Neddermann, C. H. J. Ng, A. Ossó, K. Pankatz, K. Pegion, G. C. Recalde-Coronel, A. Reintges, C. Renkl, B. Solaraju-Murali, A. Spring, C. Stan, Y. Q. Sun, C. R. Tozer, N. Vigaud, S. Woolnough, and S. Yeager (2020), Current and emerging developments in subseasonal to decadal prediction. Bulletin of the American Meteorological Society, 101(6), E869-E896. https://doi.org/10.1175/BAMS-D-19-0037.1.

Switanek, Matthew & Barsugli, Joseph & Scheuerer, Michael & Hamill, Thomas. (2020). Present and Past Sea Surface Temperatures: A Recipe for Better Seasonal Climate Forecasts. Weather and Forecasting. 35. 10.1175/WAF-D-19-0241.1.

DeFlorio, M. J., D. E. Waliser, B. Guan, F. M. Ralph, and F. Vitart (2019a), Global evaluation of atmospheric river subseasonal prediction skill. Climate Dynamics, 52: 309. doi:10.1007/s00382-0184309-x.

DeFlorio, M. J., D. E. Waliser, F. M. Ralph, B. Guan, A. Goodman, P. B. Gibson, S. Asharaf, L. Delle Monache, Z. Zhang, A. C. Subramanian, F. Vitart, H. Lin, and A. Kumar (2019b), Experimental subseasonal-to- seasonal (S2S) forecasting of atmospheric rivers over the Western United States. Journal of Geophysical Research - Atmospheres (S2S Special Issue), 124, 11,242-11,265. Doi:10.1029/2019JD031200

Gibson, P. B., D. E. Waliser, and M. J. DeFlorio (2019), A critical examination of a newly proposed interhemispheric teleconnection to Southwestern US winter precipitation. Nature Communications, 10, 2687. https://doi.org/10.1038/s41467-019-10528-y.