Data Source
This viewer displays data from the NOAA National Water Model (NWM) Retrospective Dataset v3.0,
hosted on the AWS Open Data Registry.
The National Water Model is a hydrologic modeling framework that simulates observed and forecast
streamflow over the entire continental United States (CONUS).
Data Provider
- Provider: National Oceanic and Atmospheric Administration (NOAA)
- Dataset: National Water Model Retrospective Dataset
- Version: 3.0
- Coverage: February 1979 - February 2023
- Resolution: 1km grid (LDASOUT), NHDPlus reaches (CHRTOUT)
- Registry: AWS Open Data - NWM Archive
Products Available
Land Surface (LDASOUT): Gridded 1km resolution data including:
- Snow Water Equivalent (SNEQV)
- Snow Depth (SNOWH)
- Snow Cover Fraction (FSNO)
- Soil Moisture at multiple depths
- Evapotranspiration (ACCET)
Channel Routing (CHRTOUT): Stream reach-based data including:
- Streamflow
- Stream Velocity
- Surface Runoff
Technical Notes
The NWM Retrospective v3.0 uses ECMWF ERA5 atmospheric forcing data to drive the model
simulations. The land surface model output (LDASOUT) is provided on a 1km Lambert Conformal
Conic grid covering CONUS.
Data is stored in Zarr format for efficient cloud-native access, allowing partial reads
of only the geographic regions and time periods needed.
Disclaimer
Important: This data is provided for informational and educational purposes only.
The NWM Retrospective is model output, not direct observations, and should not be used for
operational decision-making without understanding its limitations.
The National Water Model simulations may contain errors and uncertainties. Users should
consult official NOAA sources and local authorities for operational water resource management
and flood forecasting decisions.
License
NWM data is provided by NOAA and is in the public domain. There are no restrictions on
the use of this data.