Operational Hydrology with NOAA’s National Water Model: Current Capabilities and Future Enhancements

Recently upgraded to version 3.0, the National Water Model (NWM) supports a wide range of operational hydrologic decision applications. It provides 24x7 guidance for streamflow and other hydrologic components used by NWS River Forecast Centers, the Federal Emergency Management Agency and other government entities, along with research and commercial sectors. Based on the WRF-Hydro software architecture, it has been rapidly upgraded through six versions via a partnership between the NWS Office of Water Prediction (OWP), the National Center for Atmospheric Research (NCAR) and the National Centers for Environmental Prediction (NCEP).

National Water Model v3.0 became operational in 2023, building on the capabilities of version 2.2 It provides first-time total water level forecasts for coastal areas of the CONUS, Puerto Rico, the U.S. Virgin Islands, and Hawaii. Complementing existing regional products, the system simulates and forecasts the additive impacts of storm surge, tides and freshwater flow, providing guidance on compound flooding for coastal regions that are home to millions of people. NWM v3.0 also features first-time model coverage for portions of Alaska, including the Cook Inlet, Copper River Basin, and Prince William Sound regions. Several aspects of the NWM were tailored to optimize performance in this new domain. These included coupling to a glacier model, use of a customized set of forcing inputs and the ability to ingest RFC-supplied glacial lake outburst flood forecasts. Beyond those upgrades, v3.0 features improved hydrologic and land surface parameters, enhanced reservoir modules, use of an improved Multi-Radar Multi-Sensor precipitation dataset, and ingest of National Blend of Models precipitation forecast data.

This presentation provides an overview of current operations and details on enhancements to TWL simulation capabilities arriving with NWM v3.1. It will also preview the upcoming transition to the Next Generation Water Resources Modeling Framework (NextGen) with NWM v4.0, currently under development by OWP. The NextGen Framework is a model-agnostic, standards-based, open-source, water resources model interoperability software framework, designed to speed the research to operations pathway in water prediction. Its design supports execution of different model formulations and process modules in different portions of the simulation domain, standardized connection points for community-authored modules, a low overhead for developers and an architecture for execution on laptops to supercomputers. NWM use of the NextGen Framework is targeted for early 2026.