This dataset contains modeled hourly streamflow in cubic meters per second at each of about eighteen thousand selected operational and water-quality stream gage locations. It was assembled from publicly available retrospective V2.1 National Water Model outputs (See NWM Retrospective source info). The streamflow variable was extracted from model output files and the data were reshaped to optimize read performance. The stream gage locations were derived from several ongoing USGS project gages for evaluation of streamflow, water quality, and real-time monitoring, however only National Water Model identifiers and NHDPlusV2.1 catchment outlet locations (as contained in the National Water Model output files) are used to identify model results. Relationships between U.S. Geological Survey National Water Information Service gages and National Water Model prediction locations were not reviewed for release at the time of publication of this data. Please contact the author for up-to-date inf ...

The NOAA National Water Model Retrospective dataset contains input and output from multi-decade CONUS retrospective simulations. These simulations used meteorological input fields from meteorological retrospective datasets. The output frequency and fields available in this historical NWM dataset differ from those contained in the real-time operational NWM forecast model. Additionally, note that no streamflow or other data assimilation is performed within any of the NWM retrospective simulations

One application of this dataset is to provide historical context to current near real-time streamflow, soil moisture and snowpack conditions. The retrospective data can be used to infer flow frequencies and perform temporal analyses with hourly streamflow output and 3-hourly land surface output. This dataset can also be used in the development of end user applications which require a long baseline of data for system training or verification purposes.


Details for Each Version of the NWM Retrospective Output

CONUS Domain - CONUS retrospective output is provided by all four versions of the NWM

1. Version 3.0 - A 44-year (February 1979 through January 2023) retrospective simulation using version 3.0 of the National Water Model.
2. Version 2.1 - A 42-year (February 1979 through December 2020) retrospective simulation using version 2.1 of the National Water Model.
3. Version 2.0 - A 26-year (January 1993 through December 2018) retrospective simulation using version 2.0 of the National Water Model.
4. Version 1.2 - A 25-year (January 1993 through December 2017) retrospective simulation using version 1.2 of the National Water Model.
   
   

1. Versions 3.0 and 2.1: NWM Retrospective simulations used forcing from the Office of Water Prediction Analysis of Record for Calibration (AORC) dataset. NWM v2.1 used AORC v1.0 for 1979-2006 and AORC v1.1 for 2007-2020, while NWM v3.0 used AORC v1.1 for the full v3.0 (1979-2023 period)

1. Version 3.0 - AORC Alaska forcing was used to drive the NWM Alaska simulation, while North American Regional Reanalysis (NARR) data along with precipitation from the Alaska Pacific River Forecast Center (APRFC) was used to drive the Hawaii retrospective simulation. Similarly, the Puerto Rico / US Virgin Island retrospective simulation was driven by NARR data along with precipitation from the Southeast River Forecast Center.
   
   

1. NWM V3.0: All model output and forcing input fields are available in the NetCDF format. All model output fields along with the precipitation forcing field are available in the Zarr format.
2. NWM V2.1: All model output and forcing input fields are available in the NetCDF format. Many of the model output fields along with the precipitation forcing field are available in the Zarr format
3. NWM V2.0: All model output fields are available in NetCDF format. Model channel output including streamflow and related fields are available in Zarr format.
4. NWM V1.2: All model output fields are available in NetCDF format.
   
   A table listing the data available within each NetCDF and Zarr file is located in the 'documentation page'. This data includes meteorological NWM forcing inputs along with NWM hydrologic and land surface outputs, and varies by version number.

The National Water Model (NWM) is a water forecasting model operated by the National Water Center (NWC) of the NOAA National Weather Service. The NWM continually forecasts flows on 2.7 million stream reaches covering 3.2 million miles of streams and rivers in the continental United States [1]. It operates as part of the national weather forecasting system, with inputs from NOAA numerical weather prediction models, and from weather and water conditions observed through the US Geological Survey's National Water Information System. Reference materials for the computational framework behind NWM is published by NCAR [9] [10].

The NWC generates NWM streamflow forecasts for the continental US (CONUS) with multiple forecast horizons and time steps. Due to the output file sizes, these are normally not available for download more than a couple days at a time [2]. However, for a time a 40-day rolling window of these forecasts was maintained by HydroShare at RENCI [3], and a complete retrospective (August 2016 to the present) of the NWM Analysis & Assimilation outputs is maintained as well (contact help@cuahsi.org for access).

An archive of all NWM forecasts for the period Aug 18 to Sept 10, 2017 has been compiled at RENCI [4] [5], available as netCDF (.nc) files totaling 8TB. These can be browsed, subsetted, visualized, and downloaded (see [6] [7] [8]). In addition to these output files, we have uploaded to this HydroShare resource the input parameter files needed to re-run the NWM for the Harvey period, or for any time period covered by NWM v1.1 and 1.2 (August 2016 to this publication date in August 2018). These parameter files are also made available at [1].

See README for further details and usage guidance. Please see NOAA contacts listed on [1] for questions about the NWM data contents, structure and formats. Contact help@cuahsi.org if any questions about HydroShare-based tools and data access.

References [1] Overview of the NWM framework and output files [http://water.noaa.gov/about/nwm] [2] Free access to all National Water Model output for the most recent two days [http://water.noaa.gov/about/nwm - scroll down to links under "Downloading Output"] [3] NWM outputs for rolling 40-day window, maintained by HydroShare [link is no longer available] [4] Archived Harvey NWM outputs via RENCI THREDDS server [http://thredds.hydroshare.org/thredds/catalog/nwm/harvey/catalog.html] [5] RENCI is an Institute at the University of North Carolina at Chapel Hill [6] Live map for National Water Model forecasts [http://water.noaa.gov/map] [7] NWM Forecast Viewer app [no longer available] [8] CUAHSI JupyterHub example scripts for subsetting NWM output files [https://hydroshare.org/resource/3db192783bcb4599bab36d43fc3413db/] [9] WRF-Hydro Overview [https://ral.ucar.edu/projects/wrf_hydro/overview] [10] WRF-Hydro User Guide 2015 [https://ral.ucar.edu/sites/default/files/public/images/project/WRF_Hydro_User_Guide_v3.0.pdf]

This dataset contains modeled hourly streamflow at each about eighteen thousand selected operational and water quality stream gage locations. It was assembled from publicly available retrospective and operational V1.2 National Water Model outputs. The streamflow variable was extracted from model output files and the data were reshaped to optimize read performance. The stream gage locations were derived from several ongoing USGS projects using gages for evaluation of streamflow, water quality, and real-time monitoring however only National Water Model identifiers and NHDPlus catchment outlet locations are used to identify model results. Relationships between NWIS gages and National Water Model prediction locations were not reviewed for release at the time of publication of this data. Please contact the author for up to date information. All processing resources used for data reformatting and extraction can be found in this repository: https://code.usgs.gov/water/nwm_subset. This su ...

The National Water Model (NWM) is a water resources model that simulates and forecasts water budget variables, including snowpack, evapotranspiration, soil moisture and streamflow, over the entire continental United States (CONUS). The model, launched in August 2016, is designed to improve the ability of NOAA to meet the needs of its stakeholders (forecasters, emergency managers, reservoir operators, first responders, recreationists, farmers, barge operators, and ecosystem and floodplain managers) by providing expanded accuracy, detail, and frequency of water information. It is operated by NOAA’s Office of Water Prediction. This bucket contains a four-week rollover of the Short Range Forecast model output and the corresponding forcing data for the model. The model is forced with meteorological data from the High Resolution Rapid Refresh (HRRR) and the Rapid Refresh (RAP) models. The Short Range Forecast configuration cycles hourly and produces hourly deterministic forecasts of streamflow and hydrologic states out to 18 hours.

The National Water Model (NWM) is a water forecasting model operated by the NOAA National Weather Service that continually forecasts flows on 2.7 million stream reaches covering 3.2 million miles of streams and rivers in the continental United States [1]. It operates as part of the national weather forecasting system, with inputs from NOAA numerical weather prediction models, and from weather and water conditions observed through the US Geological Survey's National Water Information System. Reference materials for the computational framework behind NWM is published by NCAR [9] [10].

The NWC generates NWM streamflow forecasts for the continental US (CONUS) with multiple forecast horizons and time steps. Due to the output file sizes, these are normally not available for download more than a couple days at a time [2]. A 40-day rolling window of these forecasts is maintained by HydroShare at RENCI [3], and a complete retrospective (August 2016 to the present) of the NWM Analysis & Assimilation outputs is maintained as well (contact help@cuahsi.org for access).

An archive of all NWM forecasts for the period Aug 29 to Sept 17, 2017 has been compiled at RENCI [4] [5], available as netCDF (.nc) files totaling 6.8 TB. These can be browsed, subsetted, visualized, and downloaded (see [6] [7] [8]). In addition to these output files, we have uploaded to this HydroShare resource the input parameter files needed to re-run the NWM for the Irma period, or for any time period covered by NWM v1.1 and 1.2 (August 2016 to this publication date in August 2018). These parameter files are also made available at [1].

See README for further details and usage guidance. Please see NOAA contacts listed on [1] for questions about the NWM data contents, structure and formats. Contact help@cuahsi.org if any questions about HydroShare-based tools and data access.

References [1] Overview of the NWM framework and output files [http://water.noaa.gov/about/nwm] [2] Free access to all National Water Model output for the most recent two days [ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/nwm] [3] NWM outputs for rolling 40-day window, maintained by HydroShare [http://thredds.hydroshare.org/thredds/catalog/nwm/catalog.html] [4] Archived Irma NWM outputs via RENCI THREDDS server [http://thredds.hydroshare.org/thredds/catalog/nwm/irma/catalog.html] [5] RENCI is an Institute at the University of North Carolina at Chapel Hill [6] Live map for National Water Model forecasts [http://water.noaa.gov/map] [7] NWM Forecast Viewer app [https://hs-apps.hydroshare.org/apps/nwm-forecasts] [8] CUAHSI JupyterHub example scripts for subsetting NWM output files [https://hydroshare.org/resource/3db192783bcb4599bab36d43fc3413db/] [9] WRF-Hydro Overview [https://ral.ucar.edu/projects/wrf_hydro/overview] [10] WRF-Hydro User Guide 2013 [https://ral.ucar.edu/sites/default/files/public/images/project/WRF_Hydro_User_Guide_v3.0.pdf]

(Prototype - Under Development. Not to be relied upon for operational use.)This interactive web map shows real-time flood conditions across the United States and combines multiple informational layers to assist with River Forecast Center Decision Support Services for both internal and external partner use. This includes current and forecast flood conditions at service locations in the United States using live data from the National Weather Service Advanced Hydrologic Prediction System (AHPS) along with National Water Model (NWM) streamflow guidance across 2.7 Million reaches. In addition, current USGS streamflow observations along with NRCS snotel network observations can be viewed on top of a host of additional NOAA product layers including current radar and satellite imagery, past and future rainfall estimates, snowpack analysis, drought analysis, river and flash flood outlooks, weather hazard outlooks, severe weather, tropical outlook and cyclone forecasts, active hurricane tracks, and climate outlooks along with a variety of hydrologic, political and federal agency boundaries. Many of these layers have multiple temporal scales and all are viewable on top of standard basemaps, including world topographic maps.For a map that focuses on more general weather reports and current radar, see the Severe Weather Map.For a map that focuses on available National Water Model flow and anomaly layers, see the NWM Map.By using this AGOL web map, the user acknowledges that the NWM v1.0 output is prototype guidance and should not be considered an official NWS river forecast.About the data:Stream Gauges: This is Esri's Live Stream Gauges layer, symbolized to show only those gauges that are currently at or above flood stage. Click on a gauge to see the current depth, flow rate, and alert level. Five day forecasts from Advanced Hydrologic Prediction Service are shown where available.Population Density: This is Esri's World Population Estimate, which models the likely population of each 250 meter square cell, globally. It provides import context to the map, showing where flooding is likely to have a human impact.Flood Warnings (short and long term): These weather alerts are NOAA Weather Warnings, Watches, and Advisory data provided through the Common Alerting Protocol (CAP) Alert system. The long term warnings (flood warnings) are done on a county basis, while the short term warnings (flash flood and marine warnings) are more spatially precise. 72-hour Precipitation Forecast: This is the Quantitative Precipitation Forecast (QPF) from NOAA's National Digital Forecast Database. By default it shows the predicted total over the next 72 hours, but this forecast can also be viewed in six hour intervals.***** IMPORTANT disclaimer concerning NWM output *****The Office of Water Prediction (OWP) National Water Center is now producing water information from our National Water Model (NWM) version 1.0. Information about the prototype NWM output displayed on this map interface can be found in this Product Description Document. More information about the NWM is available athttp://water.noaa.gov/about/nwm. As this output is from the first version of the NWM, it does not yet contain information on the anthropogenic effects on streamflow and output should be viewed with caution. The output is undergoing extensive validation and verification to identify where updates to the science model parametrization and configurations can make the most improvements to the model output. The next version of the NWM will be released in the spring 2017 time frame. For official NWS river forecasts please see http://water.weather.gov.There is a NWM mapping interface in progress. In addition to the prototype NWM streamflow information, data layers of 2 snow products from the National Snow Analysis, Snow Depth and Snow Water Equivalent, are also available. The OWP is seeking to improve the availability and quality of its products and services based on user feedback. Comments regarding the Prototype Water Information Interface Webpage should be provided through the electronic survey via the link provided below: http://www.nws.noaa.gov/survey/nws-survey.php?code=NWMV1OUTPUTThe OWP also provides a range of NWS official water information through the following web sites.River observation and forecast information: http://water.weather.gov/ahpsSnow Information: http://www.nohrsc.noaa.govPrecipitation Frequency Estimates: http://www.nws.noaa.gov/oh/hdscContent from the sites above will be migrated to this new site over the next couple of years.Comments? Questions? Please Contact nws.nwc.ops@noaa.gov.By using this AGOL web map, the user acknowledges that the NWM v1.0 output is prototype guidance and should not be considered an official NWS river forecast.

This resource contains data which underpins the National Water Model (NWM) version 2.1 analyses presented in the article "NOAA's National Water Model: Advancing Operational Hydrology Through Continental-Scale Modeling" appearing in the Journal of the American Water Resources Association. Please see the readme.txt file below for details on spatial and temporal coverage.

This HydroShare resource provides Jupyter Notebooks with instructions and code for accessing and subsetting the NOAA National Water Model CONUS Retrospective Dataset. There are two Jupyter Notebooks 1. NWM_output_variable_retrieval_with_FeatureID.ipynb 2. NWM_output_variable_retrieval_with_shapefile.ipynb The first retrieves data for one point (feature ID). The second retrieves data for areas specified interactively or via an uploaded shapefile. These notebooks programmatically retrieve the data from Amazon Web Services (https://registry.opendata.aws/nwm-archive/), and in the case of Zone data retrieval average the data over the zones specified. The notebooks provided are coded to retrieve data from NWM retrospective analysis version 3.0 released in ZARR format in December 2023. The NOAA National Water Model Retrospective dataset contains input and output from multi-decade CONUS retrospective simulations (https://registry.opendata.aws/nwm-archive/ ). These simulations used meteorological input from retrospective data. The output frequency and fields available in this historical NWM dataset differ from those contained in the real-time operational NWM forecast model. Additionally, note that no streamflow or other data assimilation is performed within any of the NWM retrospective simulations

National Water Model(NWM) Stream Analysis Web Service is built by processing the analysis assimilation output of the National Water Model river network based data. All output of the river network dataset have the same geospatial extent covering all of CONUS with partial coverage into Canada and Mexico. Currently, the service contains two layers: one depicting streamflow values and the other indicating streamflow anomalies.Each layer contains 6 sub layers each with varying levels of simplification and filtering to make visualization more performant. There is also an additional labels layer which shows known stream names at the lowest scale. The streamflow layer colorizes streams according to the rate in which water is flowing through the stream while the anomaly layer colorizes streams according to how far their flow values deviate from normal flow values. All flow values are in cubic feet per second (CFS). Model Output Version: v3.0.Update Frequency: Every 30 minutes.Link to Additional Information on NWMLink to NWM graphical pageLink to metadataQuestions/Concerns about the service, please contact the DISS GIS teamTime Information:This service is not time enabled

This resource provides users with valuable access to the NOAA National Water Model (NWM) CONUS Retrospective Dataset version 2.1. The data, offered in Zarr format, can be downloaded and converted into user-specific CSV files, corresponding to individual forecast points identified by the user. Accompanying the code, users will discover a comprehensive list of USGS stations, each corresponding to a forecast point from the NWM, aiding in the forecast precision and data extraction process. The resource is further enhanced by a station description file, providing in-depth information about various streams and drainage areas retrieved from the NHDPlus Version 2dataset. The combination of these tools and datasets offers an effective means to analyze and visualize hydrological conditions across the CONUS region, benefitting researchers, planners, and policy-makers in their water management decisions.

Rolling archive of NOAA National Water Model output. The window is about 2 weeks long.

Output files are in netCDF format and accessible via OPeNDAP at:

http://tds.renci.org:8080/thredds/catalog/nwm/catalog.html

The NOAA website for the National Water Model is at:

http://water.noaa.gov/about/nwm

This service is built by processing the analysis assimilation output of the National Water Model land based data. All output of the land dataset have the same geospatial extent covering all of CONUS with partial coverage into Canada and Mexico. Currently, the only layer within the service is near-surface soil moisture saturation. The near-surface soil moisture saturation layer shows moisture saturation of the top 40cm of the soil. Model Output Version: v2.1See https://water.noaa.gov/about/nwm for further details about this data.Link to graphical web page: https://water.noaa.gov/mapLink to data download: https://nomads.ncep.noaa.gov/pub/data/nccf/com/nwm/prod for raw data files in netcdf format.

This data release presents truth data and benchmark results describing simulation of hydrologic drought events in the conterminous United States. This data release supports a publication (Simeone and others, 2024) which documents drought benchmarking methods and their application to the results of the National Water Model (NWM) version 2.1. Truth data used were observations at U.S. Geological Survey streamgages across the conterminous United States. These data include 4662 U.S. Geological Survey streamgages with a historical period from 1984-2016. The following files are included in this data release: 1) kappa_long_nwm.csv: Benchmark results for the Cohen's kappa evaluation metrics in long table format. 2) spear_bias_dist_long_nwm.csv: Benchmark results for the Spearman's, bias, and distributional evaluation metrics in long table format. 3) ann_eval_long_nwm.csv: Benchmark results for the annual drought evaluation metrics in long table format. 4) streamflow_percentiles_nwm.zip: A zip file containing individual streamflow percentile data files used in this analysis as truth data. 5) input_data_nwm.zip: A zip file with input data for individual streamgages used for our data analysis pipeline as truth data. 6) streamflow_gages_in_study.csv: Metadata information for the 4662 U.S. Geological Survey streamgages contained in the above datasets.

(Prototype - Under Development. Not to be relied upon for operational use.)This interactive web map shows real-time flood conditions across the United States and combines multiple informational layers to assist with River Forecast Center Decision Support Services for both internal and external partner use. This includes current and forecast flood conditions at service locations in the United States using live data from the National Weather Service Advanced Hydrologic Prediction System (AHPS) along with National Water Model (NWM) streamflow guidance across 2.7 Million reaches. In addition, current USGS streamflow observations along with NRCS snotel network observations can be viewed on top of a host of additional NOAA product layers including current radar and satellite imagery, past and future rainfall estimates, snowpack analysis, drought analysis, river and flash flood outlooks, weather hazard outlooks, severe weather, tropical outlook and cyclone forecasts, active hurricane tracks, and climate outlooks along with a variety of hydrologic, political and federal agency boundaries. Many of these layers have multiple temporal scales and all are viewable on top of standard basemaps, including world topographic maps.For a map that focuses on more general weather reports and current radar, see the Severe Weather Map.For a map that focuses on available National Water Model flow and anomaly layers, see the NWM Map.By using this AGOL web map, the user acknowledges that the NWM v1.0 output is prototype guidance and should not be considered an official NWS river forecast.About the data:Stream Gauges: This is Esri's Live Stream Gauges layer, symbolized to show only those gauges that are currently at or above flood stage. Click on a gauge to see the current depth, flow rate, and alert level. Five day forecasts from Advanced Hydrologic Prediction Service are shown where available.Population Density: This is Esri's World Population Estimate, which models the likely population of each 250 meter square cell, globally. It provides import context to the map, showing where flooding is likely to have a human impact.Flood Warnings (short and long term): These weather alerts are NOAA Weather Warnings, Watches, and Advisory data provided through the Common Alerting Protocol (CAP) Alert system. The long term warnings (flood warnings) are done on a county basis, while the short term warnings (flash flood and marine warnings) are more spatially precise. 72-hour Precipitation Forecast: This is the Quantitative Precipitation Forecast (QPF) from NOAA's National Digital Forecast Database. By default it shows the predicted total over the next 72 hours, but this forecast can also be viewed in six hour intervals.***** IMPORTANT disclaimer concerning NWM output *****The Office of Water Prediction (OWP) National Water Center is now producing water information from our National Water Model (NWM) version 1.0. Information about the prototype NWM output displayed on this map interface can be found in this Product Description Document. More information about the NWM is available athttp://water.noaa.gov/about/nwm. As this output is from the first version of the NWM, it does not yet contain information on the anthropogenic effects on streamflow and output should be viewed with caution. The output is undergoing extensive validation and verification to identify where updates to the science model parametrization and configurations can make the most improvements to the model output. The next version of the NWM will be released in the spring 2017 time frame. For official NWS river forecasts please see http://water.weather.gov.There is a NWM mapping interface in progress. In addition to the prototype NWM streamflow information, data layers of 2 snow products from the National Snow Analysis, Snow Depth and Snow Water Equivalent, are also available. The OWP is seeking to improve the availability and quality of its products and services based on user feedback. Comments regarding the Prototype Water Information Interface Webpage should be provided through the electronic survey via the link provided below: http://www.nws.noaa.gov/survey/nws-survey.php?code=NWMV1OUTPUTThe OWP also provides a range of NWS official water information through the following web sites.River observation and forecast information: http://water.weather.gov/ahpsSnow Information: http://www.nohrsc.noaa.govPrecipitation Frequency Estimates: http://www.nws.noaa.gov/oh/hdscContent from the sites above will be migrated to this new site over the next couple of years.Comments? Questions? Please Contact nws.nwc.ops@noaa.gov.By using this AGOL web map, the user acknowledges that the NWM v1.0 output is prototype guidance and should not be considered an official NWS river forecast.

An example for accessing NWM retrospective streamflow predictions using Python and Zarr.

• https://registry.opendata.aws/nwm-archive/ The NOAA National Water Model Retrospective dataset contains input and output from multi-decade CONUS retrospective simulations. These simulations used meteorological input fields from meteorological retrospective datasets. The output frequency and fields available in this historical NWM dataset differ from those contained in the real-time operational NWM forecast model. One application of this dataset is to provide historical context to current near real-time streamflow, soil moisture and snowpack conditions. The retrospective data can be used to infer flow frequencies and perform temporal analyses with hourly streamflow output and 3-hourly land surface output. This dataset can also be used in the development of end user applications which require a long baseline of data for system training or verification purposes.

This dataset repository contains the dataset that supports the study of Minder et al. (2024): Evaluating and Improving Snow in the National Water Model, using Observations from the New York State Mesonet. The datasets in this archive include output from distributed simulations of the WRF Hydro model, output from point simulations with the Noah-MP land surface model, and manual and automated snow water equivalent (SWE) observations at New York State Mesonet (NYSM) station locations. The formatting and file naming conventions for each dataset are described in detail in the minder_etal_NWM_snow_dataset_ReadMe.pdf file.

Session: CUAHSI Summer Institute at the National Water Center Chair: Jerad Bales (CUAHSI) The 2018 CUAHSI Summer Institute (SI) was held June 10 – July 26, 2018 at the National Water Center on the Tuscaloosa campus of the University of Alabama. Twenty-five graduate students, two course coordinators, nine faculty theme leaders, and three CUAHSI staff participated, as well as a number of guests from the NWS, USGS, and elsewhere. Students at the 2018 SI focused on hyper-resolution modeling, groundwater – surface connections, data from volunteer monitoring, and river hydraulics. Students used National Water Model outputs and observations to explore potential improvements to the NWM and to describe uncertainty. Among the data sets utilized was the CUAHSI-curated Hurricane Harvey hydrometeorological data from 2017. The session will begin with a presentation from Dr. Thomas Graziano, Chief of the NWS Office of Water Prediction, followed by presentations by selected 2018 students.

"Evaluating Alternative Baseflow Estimation Methods for Improving National Water Model Forecasting" Speaker: Joseph M. Krienert (Southern Illinois University) Co-Authors: Minki Hong (Texas A&M University), Ritesh Karki (Auburn University), and Sama S. Memari (University of Alabama)

The National Water Model (NWM) became fully operational in August of 2016. This hydrologic model uses a framework of real time climatic data and observed physiographic attributes to produce forecasts of surficial fluvial systems across the Contiguous US. Comparison of the NWM streamflow estimations with USGS observed datasets has shown that the NWM estimates are not entirely accurate, especially during low flow conditions. A potential influence on this miscalculation lies in the NWM’s conceptual (not physicallyexplicit) estimation of baseflow to streams, and this non-linear conceptual baseflow model only expresses a part of the interaction between groundwater and surficial hydrology.

This research evaluates the current representation groundwater discharge in the NWM with a case study of five watersheds located within the Northern High Plains region. A comparison between USGS observed stream flow, a systematically calibrated groundwater model (Peterson et al 2016), and the output hindcasts of the NWM will be used to evaluate the current model’s fitness in representing surface water - groundwater interaction in gaining streams; with a particular focus on baseflow estimation. Based on the results of this analysis, formulation of alternative functions representing the relationship between subsurface storage and groundwater discharge will be tested for potential improvements in future updates of the NWM.

This service is built by processing the analysis assimilation output of the National Water Model land based data. All output of the land dataset have the same geospatial extent covering all of CONUS with partial coverage into Canada and Mexico. Currently, the only layer within the service is near-surface soil moisture saturation. The near-surface soil moisture saturation layer shows moisture saturation of the top 40cm of the soil. Model Output Version: v2.1See https://water.noaa.gov/about/nwm for further details about this data.Link to graphical web page: https://water.noaa.gov/mapLink to data download: https://nomads.ncep.noaa.gov/pub/data/nccf/com/nwm/prod for raw data files in netcdf format.

This service is built by processing the analysis assimilation output of the National Water Model land based data. All output of the land dataset have the same geospatial extent covering all of CONUS with partial coverage into Canada and Mexico. Currently, the only layer within the service is near-surface soil moisture saturation. The near-surface soil moisture saturation layer shows moisture saturation of the top 40cm of the soil. Model Output Version: v2.1See https://water.noaa.gov/about/nwm for further details about this data.Link to graphical web page: https://water.noaa.gov/mapLink to data download: https://nomads.ncep.noaa.gov/pub/data/nccf/com/nwm/prod for raw data files in netcdf format.