Abstract
Accurately predicting the rain is a fundamental component of weather forecasting. However, looking at the data provided for the 2018 ASA Data Expo Challenge, forecasts were consistently underpredicting the proportion of rainy days. The default threshold in inches of rain for what is considered a rainy day is 0.01 inches or more as defined by the National Weather Service. We found that adjusting the threshold for each city dramatically increases probability of precipitation forecast accuracies, and that generally across the United States a threshold of 0.07 inches is better than 0.01.
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References
Aasa A (2016) Spatial interpolation in R. http://aasa.ut.ee/LOOM02331/
Marsh D (2015) What does probability of precipitation mean?. https://www.weather.gov/lmk/pops
R Core Team R (2014) A language and environment for statistical computing. R foundation for statistical computing, Vienna, Austria. http://www.R-project.org/
Suess EA, Trumbo BE (2010) Introduction to probability, simulation and Gibbs sampling with R. Springer, New York
Wickham H (2009) ggplot2: elegant graphics for data analysis. Springer, New York
Yau N (2011) Visualize this: the flowingdata guide to design, visualization, and statistics. Wiley, Indianapolis
Acknowledgements
The authors are grateful to the organizers of the 2018 Joint Statistical Meetings, and the members of the ASA section on Statistical Graphics and the section on Statistical Computing for the opportunity to create and share our work.
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Keeley, D., Suess, E.A. Accuracy of precipitation forecasts: finding the right threshold for what is considered rain. Comput Stat 38, 1123–1134 (2023). https://doi.org/10.1007/s00180-023-01337-5
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DOI: https://doi.org/10.1007/s00180-023-01337-5