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Full catalog/S111
S111·dataset

Standardized surface current forecasts for ships (NOAA)

NOAA S-111 Surface Water Currents Data
hydrosphere NOAA NOAA active
In plain English

What it measures. Forecasts of the speed and direction of surface ocean currents in U.S. coastal waters, the Great Lakes, and some offshore areas, delivered as chart-matched map tiles.

How it's made. NOAA pulls current forecasts from its operational coastal forecast systems and global ocean model, encoding them in the international S-111 standard format.

How & where you'd use it. Built into electronic navigation charts, it helps mariners plan around currents, saving fuel and improving safety in busy waters.

What's measured

aws-pdsoceanswater

Coverage & cadence

  • Time span— → ongoing

What you can do with it

  • Follow rainfall, floods and surface-water extent
  • Track soil moisture and the onset of drought
  • Monitor lakes, rivers and groundwater storage
Official description

S-111 is a data and metadata encoding specification that is part of the S-100 Universal Hydrographic Data Model, an international standard for hydrographic data. This collection of data contains surface water currents forecast guidance from NOAA/NOS Operational Forecast Systems, a set of operational hydrodynamic nowcast and forecast modeling systems, for various U.S. coastal waters and the great lakes. The collection also contains surface current forecast guidance output from the NCEP Global Real-Time Ocean Forecast System (GRTOFS) for some offshore areas. These datasets are encoded as HDF-5 files conforming to the S-111 specification, and are geospatially subset into individual tiles conforming to the NOAA/OCS Nautical Product Tiling Scheme, with filenames indicating the corresponding NOAA Electronic Navigational Chart (ENC) Cell Identifier. A full set of S-111 tiles is created for each new model run cycle, which occurs four times per day for all models except for RTOFS, which updates only once per day. Files are organized using a path naming convention that includes the OFS identifier (e.g. 'cbofs' corresponding with output from the Chesapeake Bay Operational Forecast System) as well as the year, month, day, and hour corresponding with each model run initialization time. Each individual S-111 (HDF-5) file contains all forecast projections from a single model run for that geographic area. In other words, a single S-111 file will contain multiple gridded arrays each containing a forecast valid at a distinct time in the future, out to the forecast horizon of the underlying m

Get the data

noaa_access.py
# NOAA Open Data on AWS — public S3, no login
import s3fs

fs = s3fs.S3FileSystem(anon=True)
# find this dataset's bucket in the docs link in the sidebar, then:
# files = fs.ls("noaa-<bucket>/...")
# open NetCDF/GRIB with xarray, COGs with rioxarray
NOAA Open Data is on public AWS S3 — no login at all (anonymous access).