Time 2 Chunk (2.0), DWD ICON-EU, status for weather

Listen, my second child is arriving any minute now. This transmission will be brief. I haven't decided if I will name him Poseidon, Gefs, or Turbulence.

Zarr v3 deprecation

We're all-in on Icechunk. Our existing Zarr v3 datasets will continue updating for 90 days, at which point we will sunset them. Consider them deprecated and update to use our Icechunk Zarrs by July 23, 2026.

Speaking of which

The new access pattern:

Via dynamical-catalog

import dynamical_catalog

# Open a dataset as an xarray Dataset via its Icechunk repository
ds = dynamical_catalog.open("noaa-gfs-forecast")

To more easily ensure the right set of dependencies and to make an increasingly variable set of opening incantations more accessible, we made a python library to list and open datasets.

import dynamical_catalog

# List all available datasets
dynamical_catalog.list()

# Get the underlying Zarr store if you want even more control
store = dynamical_catalog.get_store("noaa-gfs-forecast")
ds = xr.open_zarr(store)

Via STAC

We are STAC-maxxers now. https://stac.dynamical.org/catalog.json contains ALL of the data used to create our documentation and drive the dynamical-catalog library. Point your robots at it for all the documentation they need to get going. STAC-as-skill.

ICON-EU

Deutscher Wetterdienst's ICON-EU is now a cloud-optimized, live-updating Icechunk 2.0 Zarr. High-resolution 5-day forecasts over Europe, nested from DWD's global ICON model, at the 00/06/12/18 UTC cycles.

What makes this one extra fun: as far as we can tell, no other public archive of ICON-EU exists. DWD only keeps a short rolling window on their own servers, so we'll keep growing the archive from here.

Huge thanks to:

Jack Kelly from Open Climate Fix for getting this off the ground and hoarding forecasts to kickstart the archive and to the Patrick J McGovern Foundation for supporting their work.
The DWD Open Data program
Source Cooperative for hosting the upstream grib archive
AWS Open Data for the Icechunk storage

Find it at:

Enjoy the weather,