Potential Users Evaluate Product Content and Design for Subseasonal Extreme Precipitation Forecasts

Extreme precipitation over a two-week period has been shown to cause significant impacts to life and property. Forecasting these extreme periods on the subseasonal to seasonal timeframe may provide additional time for planning, however this relies on the forecast being interpretable and trustworthy by users. The Prediction of Rainfall Extremes at Subseasonal to Seasonal Periods (PRES2iP) project team has conducted three workshops over six years to engage with stakeholders to learn what is needed for decision-making for subseasonal precipitation. The first workshop, conducted in 2018, focused on developing relationships with stakeholders across the CONUS and learning how they view extreme precipitation in the context of their work. In the second workshop, conducted virtually in 2021, stakeholders demonstrated how they use existing subseasonal products and how they manage uncertainty with longer lead times. The PRES2iP team used the knowledge gained from the first two workshops to design a suite of extreme precipitation subseasonal forecast products for the third and final workshop in April 2023. Stakeholder feedback was gathered from two testbed scenarios of 14-day extreme precipitation periods. Emerging themes show that text products alongside quantitative precipitation forecasts helped to improve interpretability when looking at longer lead times and greater uncertainty. Stakeholders also stated they would use a time-series of regional precipitation at longer leads, if the uncertainty is communicated alongside the values. Overall, there was no single product that worked best, but instead a combination of spatial and temporal products with associated narratives is needed.