Recast WOOF

Weather Observations and Open Forecasting: a GPU-native weather model you run on your own card.

WOOF is a regional weather model with WRF-class physics that runs on one NVIDIA GPU, with its own preprocessing, data assimilation and plots. One install carries three models:

Preview means the model is in the package, documented and tested on CPU, and its command says preview each time it runs; its config and checkpoint formats may change in a minor release. The major-version promise covers the regional model.

Production means the regional commands and their config and checkpoint formats are covered by that promise. It is not a statement about forecast accuracy; see Science and limits below.

Linux on x86_64, Python 3.11 or newer, an NVIDIA GPU and driver. WOOF has no Windows build of the native tools yet.

python3 -m venv ~/woof-env
~/woof-env/bin/python -m pip install 'recast-woof[all-cu12]'
~/woof-env/bin/woof fetch-tables
~/woof-env/bin/woof fetch-geog --datasets wrf
~/woof-env/bin/woof doctor

For a CUDA 13 setup use all-cu13. The hex model runs only on CUDA 13, so install all-cu13 to use it. Install one CuPy/CUDA major per environment. The Linux wheel carries the native tools (GRIB and NetCDF decoding, the WPS-equivalent preprocessor, the renderer).

fetch-geog downloads the global geography every forecast builds its terrain, land use and soil from: about 1.3 GB, 17 GB unpacked, once per computer. fetch-tables adds two Thompson microphysics tables (about 314 MiB). Reference tables and map assets arrive with the recast-woof-data package.

woof domain --point 35.3,-97.5 --source hrrr --cycle latest --hours 3 \
     --root-dx 3 --point-extent-km 300 --out forecast.toml
woof go forecast.toml --dry-run
woof go forecast.toml

--dry-run reviews the route, sizes it for your card and names anything missing; the second line fetches, prepares, runs and draws. Pictures are drawn as each history frame lands, beside the running forecast.

Compare two runs, any product, as run A minus run B:

woof render --diff runA/ runB/ --out diff/

The pair must share the grid and the valid times; a mismatch is refused by name.

• docs/public/: the CLI manual, physics, hardware guidance and data sources. The code verification record documents historical WRF v4.6.1 comparisons and their configuration and coverage limits.
• components/hex/ and components/globe/: the hex and global models' manuals, tests and tools.
• woof --help-all lists every command; woof hex --help and woof global --help list the preview models' commands.

WOOF implements a WRF-ARW-class regional model and WRF-derived physics on the GPU. Comparisons against WRF Fortran, ULP and byte-identity checks, and the matched-run and ensemble consistency comparisons are code verification: evidence that the tested code computes its intended equations. Each result belongs to the build, reference version and configuration it tested. None establishes general equivalence with WRF or skill for every combination of physics, input data and hardware.

Solution verification estimates numerical error in a particular run. Routine numerical-error budgets for weather forecasts remain a gap. Validation compares model results with observations. Meteorology calls that scoring forecast verification; in computational-science V&V terms it is validation. Matching WRF is code verification and never validates a model. WOOF can inherit WRF's published validation record only to the extent the two are statistically indistinguishable for the configuration in question.

Published observation evidence is limited to specific runs and variables, including the ASOS snow/soil comparison, the station/ceilometer fog-suite comparison and an MRMS model-top comparison. The observation scoreboard is in development. These do not establish a broad validation record across regions, seasons or forecast lengths. The evidence page documents historical WRF v4.6.1 code comparisons and their configuration and coverage limits.

The hex model is a port of the MPAS-A v8.4.1 dynamical core with this engine's physics; it is not MPAS and is not endorsed by UCAR. Use official meteorological services for forecasts and warnings.

WOOF continues an engine released before under another name: WOOF 1.0 is that engine's release 2.8.0 and the fixes made since, under the WOOF name, with the hex and global models inside it. Settings spelled GPUWM_* keep working beside the new WOOF_* spelling.

Apache License 2.0. Third-party code, tables and datasets keep their own terms; see NOTICE and licenses/.