WRF-Hydro and the National Water Model


Over the past four years, a team of RAL scientists and engineers have developed and transitioned the community WRF-Hydro modeling system into the National Water Model (NWM), the first operational, high-resolution, physics-based hydrologic prediction model ever implemented across the continental U.S.  Developed in close collaboration with the National Weather Service (NWS) Office of Water Prediction, the USGS, and a number of university partners, the RAL team delivered the first version of the model in only one year (two years ahead of schedule) on a modest budget. The model is now being used, to solve a complex problem—tracking water flow across the country to aid local communities and emergency managers in responding to water-related threats.  It is also providing consistent, reliable, high-resolution data to decision makers across the country, helping them address increasingly complex societal issues related to flooding, drought, water availability and water quality. In addition to providing significant benefit to the operational community, the NWM is proving to be a valuable tool in the conduct of research and as a mechanism for moving research to operations.  The NWM provides an important bridge between the numerical weather prediction community and the terrestrial hydrology community. As an open source, open platform model, the NWM and WRF-Hydro will continue to evolve to meet the nation’s complex needs for water resource planning and management information while also providing a seamless pathway for academic researchers to innovate new improvements in water prediction. 

Notable Recognition - National

In September 2017 the Department of Commerce recognized the development and implementation of the National Water Model with a Gold Medal for Scientific/Engineering Achievement; this is the highest award given by the agency. The award noted that “the NWM is the first high-resolution CONUS-wide water forecast model executed in the operational NOAA supercomputing environment.  It provides first-of-its-kind water resource guidance to NWS River Forecast Centers and other end users…” The NOAA/NCAR development team was specifically praised for demonstrating “exceptional dedication, hard work, expertise, and creativity.”  The WRF-Hydro modeling system, which was developed at NCAR, has been successfully transitioned into the nation’s new state-of-the-art operational water prediction system through this exemplary NOAA/NCAR partnership.

Local Recognition

In December of 2017, the NCAR WRF-Hydro/NWM development team within the Research Applications Laboratory was awarded an Outstanding Accomplishment for Scientific and Technical Advancement for the development and implementation the National Water Model, the first operational, high-resolution, hydrologic prediction model to be implemented across the continental U.S.

Accomplishments & Goals:

FY2018 National Water Model (NWM) Version 2.0 development lead to many scientific and technical advancements which include but are not limited to the following.

  • Development and implementation of the NWM for Hawaii (oCONUS or regions affiliated with the U.S. but outside of the contiguous lower 48 states) became the first step in providing calibrated, 24/7 analysis and hydrologic forecast service in this region.
  • The implementation of advanced hydrologic model parameter estimation, calibration, and regionalization methods increased the skill in NWM analyses and forecasts.
  • Both the assimilation of higher quality observational data and the implementation of a new Analysis and Assimilation cycle configured to the Long Range forecast provided improved initial conditions in all forecast configurations of the NWM.
  • A baseline capability for ensemble seasonal water supply forecasting in the western U.S. was established to demonstrate and provide quantitative evidence of ensemble seasonal water supply forecasts in the western U.S.
  • In an effort to lower the barrier to entry for new hydrologic modelers and thus to rapidly engage researchers both within NOAA and throughout the broader academic community in the research and development process the team began the first year of a three year effort to improve the NWM code base modularity.

FY2019 Goals for NWM Version 2.1 include improvements to the whole WRF-Hydro/NWM Ecosystem and suite of tools as well as focusing on engaging and training our community partners. Listed below are some of the overarching themes.

  • Expand the oCONUS domain and implementing NWM for Puerto Rico
  • Improve the meteorological forcings in terms of downscaling and rain/snow partitioning
  • Improve the land use and land cover representation by using a dynamic land cover specification
  • Improve computational performance
  • Continue code modularization efforts
  • Engage NWS River Forecast Centers with individual hands-on training
 Figure 1. The NWM/WRF-Hydro Ecosystem and suite of tools

Figure 1. The NWM/WRF-Hydro Ecosystem and suite of tools

WRF-Hydro Modeling System Project

During FY2018 the  Community WRF-Hydro code base merged with the National Water Model (NWM) code base. On the ‘back end’ the NCAR WRF-Hydro team has and supports one unified code base and set of model pre/post processing tools for the community. On the ‘front end’, the community has access to the configuration of an operational model which is rarely done and makes it available for use in research applications, providing opportunities for collaboration on model development, evaluation, and improvement. Along with this came a new public version 5 model source code release complete with supporting documentation and user guides, pre-processing, and post-processing tools. The model source code is now hosted in a public GitHub repository and available for model developers to log issues and contribute. To better serve and support the community the team redesigned their website, and implemented a helpdesk ticketing system and a contact form to assist WRF-Hydro users. An email listserv was set up to announce new code releases and the availability of new tools as well as communicate news and events. To meet the demands of an eager and rapidly expanding hydrologic modeling community the NCAR WRF-Hydro team took significant strides to improve both the process logistics as well as the technical content and delivery of 2 hands-on WRF-Hydro Training Workshops co-organized and co-hosted with the Consortium of Universities for the Advancement of Hydrologic Science, Inc.(CUAHSI).

Figure 2. Participants of the CUAHSI/NCAR October 2018 WRF-Hydro Modeling System Training Workshop
Figure 2. Participants of the CUAHSI/NCAR October 2018 WRF-Hydro Modeling System Training Workshop
Goals of FY19 are to continue to build the WRF-Hydro community by:
  • Implementing a User’s forum, a place where users can discuss issues related to WRF-Hydro and collaborate

  • Providing a News outlet such as Twitter to connect with hydrologic communities

  • Providing a full online training suite to reach those users who are unable to attend the hands-on training workshops due to limited seating

  • Translating our model documentation and user guides into Spanish to reach our Latin American and Spanish speaking users around the globe