dataset · USA
NOAA National Water Model Retrospective
NOAA National Water Model Retrospective (NOAA OWP). Access: S3 (anonymous). Formats: Zarr, NetCDF. Resolution: 1 km / reach. Coverage: USA. Pricing/licence: free.
Visit source ↗Source details
Licence: free
Evidence quality: 30.1
Verified 2026-10-16 (curl HTTP 200).
Metadata checked: 2026-10-14T13:20:00.000Z
What's in it
- Data offered docs-verified
- hourly streamflow · 3-hourly land surface output · NWM meteorological forcing inputs · hydrologic and land surface model outputs (varies by NWM version)
- Coverage docs-verified
- CONUS (v3.0 also includes Alaska, Hawaii and Puerto Rico / US Virgin Islands) · v3.0: February 1979 to January 2023; v2.1: February 1979 to December 2020; v2.0: January 1993 to December 2018; v1.2: January 1993 to December 2017
- Resolution llm-inferred
- 1 km / reach
- Update frequency docs-verified
- No updates
- Formats docs-verified
- NetCDF · Zarr
- Access docs-verified
- Open data with no restrictions on use; anonymous S3 access (AWS CLI with --no-sign-request), no AWS account required; free
Useful for
- Use cases llm-inferred
- FRA baseline flow frequency analysis from long-term hourly simulated streamflow at reach scale · Historical context for current near real-time streamflow, soil moisture and snowpack conditions · Training or verification data for flood or drainage models that need a long baseline record
- Audience llm-inferred
- flood consultants · hydrologists · drainage engineers · water resources engineers · GIS analysts
Limitations
- Constraints docs-verified
- No streamflow or data assimilation in the retrospective runs, so outputs are not observation-corrected · Retrospective output frequency and fields differ from the real-time operational NWM · Zarr holds only a subset of output fields, varying by version · Alaska, Hawaii and Puerto Rico / US Virgin Islands coverage is available only for v3.0 · Very large archive (tutorial cites 250 TB for the NWM dataset)
Evidence
Check upstream coverage, uncertainty and licence before use. Station observations are not forecasts or design levels.