An operational prototype for seasonal drought prediction in a Mediterranean region

Droughts create significant societal and environmental challenges. Accurate seasonal drought forecasting can provide early insights into potential impacts, serving as a vital resource for informed decision-making. An operational prototype with high spatial resolution is presented to predict seasonal meteorological drought in Spain (4SPAIN).The prediction system is inspired by an empirical method known as Ensemble Streamflow Prediction (ESP; Day, 1985). The model forecasts drought using the Standardized Precipitation Index (SPI6; Mckee et al., 1993) based on accumulated monthly precipitation data over 6 months (Turco et al., 2017). Due to the near real-time availability of ERA5 and its high similarity with the Spanish Meteorological Agency Spanish database (Torres-Vázquez et al., 2023), this database was chosen for the development and implementation of 4SPAIN. The validation of the model shows that it has predictive skill generally up to four-month lead time, whereas worse results come from predicting the wet season.Finally, an online operational prediction system called "Drought forecast monitor for Spain" was implemented. This low computational cost tool can provides users and competent authorities with an interactive interface to make early decisions based on updated information about the magnitude of the drought, uncertainty, alert level, and the probability of moderate drought occurrences (https://matv.shinyapps.io/app_4SPAIN/).ReferencesDay, G. N. (1985). Extended streamflow forecasting using NWSRFS. Journal of Water Resources Planning and Management, 111(2), 157–170.McKee, T. B., Doesken, N. J., y Kleist, J. (1993). The relationship of drought frequency and duration to time scales. In Eighth Conference on Applied Climatology, January, Anaheim, California, 1993, pages 17–22. American Meteorological Society.Torres-Vázquez, M. Á., Halifa-Marín, A., Montávez, J. P., & Turco, M. (2023). High resolution monitoring and probabilistic prediction of meteorological drought in a Mediterranean environment. Weather and Climate Extremes, 40, 100558.Turco, M., Ceglar, A., Prodhomme, C., Soret, A., Toreti, A., & Francisco, J. D. R. (2017). Summer drought predictability over Europe: empirical versus dynamical forecasts. Environmental research letters, 12(8), 084006.Acknowledgements A.G. thanks  to the Ministerio de Ciencia, Innovación y Universidades of Spain for PhD contract FPU19/06536. M.T. acknowledges funding by the Spanish Ministry of Science, Innovation and Universities through the Ramón y Cajal Grant Reference RYC2019-027115-I and through the project ONFIRE, Grant PID2021-123193OB-I00, funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”.