UFS Forecast Model Evaluation and Improvement for S2S Hydrometeorological Prediction in the Western United States

Hydrometeorological extremes threaten our interconnected food, water, and energy security and currently cause hundreds of deaths and billions of US dollars in damage annually. Improving our predictions of such events at subseasonal timescales of weeks 2-5 offers an opportunity to enhance our early warning planning to minimize extreme event impacts. This presentation will give an overview of a new NOAA project focused on Western States sub seasonal hydrometeorological prediction. The project plans to improve the NOAA Unified Forecast System (UFS) land model and land-atmosphere interactions to improve precipitation and surface hydrology (snowpack, near surface soil moisture, and streamflow) forecasts across the Western US at the weeks 2-5 subseasonal scale. Specifically, improvements to UFS subseasonal precipitation (primarily spring and summer precipitation) and year-round hydrology forecast skill across the Western US are targeted. Novel statistical evaluation, model optimization techniques and the Hierarchical System Development (HSD) paradigm for the UFS will be leveraged to provide rapid iteration and evaluation of changes to the UFS land model, Noah-Multiparameterization (Noah-MP). The combination of techniques should also permit a deeper process level understanding within Noah-MP and land-atmosphere coupling, including improved understanding of causality within the coupled model -- that is, answering why a particular model behavior is seen.

We will also discuss how this project intends to collaborate with other efforts focused on UFS land model and land-atmosphere coupling improvements and evaluations. These include activities to improve the METplus model evaluation software with eventual transitions to the NOAA/Environmental Modeling Center (EMC) EMC Verification System (EVS) by developing capabilities to ingest new in situ and remote sensing datasets, and to compute advanced land and land-atmosphere coupling metrics for both observations and UFS output.