Seasonal Drought Forecast For the Intermountain West
2023/2024 Winter
Figure 1: Downscaled NMME forecasts for total precipitation (left) and anomalous precipitation (right) from December 2023 to February 2024 in the Western United States. Anomalies are calculated as deviations from the mean from 2013-2023. Positive anomalies indicate above-average precipitation, while negative anomalies indicate below-average precipitation. The NMME forecasts (Kirtman et al., 2014) were trained from 1982-2012 and then statistically downscaled using the analog method (Gutmann et al., 2022), with 4-kilometer PRISM data as the observational record (Daly et al., 2008). The analog method identifies historical precipitation patterns that closely match the forecast for a specific month and uses these patterns to refine the forecast based on the resolution of the observational dataset.
References
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Gutmann, Ethan D., et al. En-GARD: A Statistical Downscaling Framework to Produce and Test Large Ensembles of Climate Projections. Journal of Hydrometeorology, 23.10 (2022): 1545-1561. doi:10.1175/JHM-D-21-0142.1.
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Kirtman, Ben P., et al. The North American multimodel ensemble: phase-1 seasonal-to-interannual prediction; phase-2 toward developing intraseasonal prediction. Bulletin of the American Meteorological Society, 95.4 (2014): 585-601. doi:10.1175/BAMS-D-12-00050.1.
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Daly, Christopher., et al. Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States. International Journal of Climatology. 28.15 (2008): 2031-2064. doi:10.1002/joc.1688
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Vernon, B., Zhang, W., and Chikamoto, Y. Statistical downscaling as a method for improving seasonal forecasting in the Western United States. (In preparation). 2024.
This utility has been developed in partnership with the Bureau of Reclamation and the Utah Agricultural Experiment Station