ArWen
Explore weather, create regional forecasts, and run them on your own hardware.
ArWen combines a native desktop application, a terminal workspace, and a
CUDA-based atmospheric modeling engine. Use the desktop to inspect weather maps,
choose a forecast area or cyclone, review the setup, and follow your results.
Run the model on a local NVIDIA GPU or a Linux computer connected over SSH.
The Linux desktop displaying a real ERA5 field. Windows uses the same interface.
Get ArWen
The desktop archives contain the applications, native map library and map assets.
Windows includes a graphical setup launcher that downloads a private Python and
CUDA runtime on first use. Linux uses the manual setup below. No Rust or C++
compiler is needed for these binary packages.
The Python package is named gpuwm. Its Windows and Linux platform wheels
include the engine, native processing tools, and TUI. The desktop GUI is the
separate download above. Check release notes and checksums
for the exact artifacts and qualification records.
Install the desktop for forecasts on your PC
Windows
- Download the Windows desktop ZIP and extract it into its own folder.
- Open ArWen.exe. The setup window installs the matching engine and GPU
dependencies, shows progress, and checks the local GPU.
- When the workspace opens, choose Create forecast, draw an area, review
the configuration, and run it on Local computer.
Python and the user-space CUDA components are managed by the application.
A compatible NVIDIA driver must already be installed. Keep the resources
folder beside ArWen.exe. Setup errors remain visible with retry and repair
controls; setup does not require terminal commands.
First setup also prepares the physics tables and global geography needed for
regional forecasts. Allow several gigabytes of downloads and at least 25 GB of
free disk space, plus space for weather inputs and forecast output.
Linux
python3 -m venv ~/.local/share/arwen/venvs/2.7.2
~/.local/share/arwen/venvs/2.7.2/bin/python -m pip install 'gpuwm[all-cu12]==2.7.2'
~/.local/share/arwen/venvs/2.7.2/bin/python -m gpuwm.cli fetch-tables
~/.local/share/arwen/venvs/2.7.2/bin/python -m gpuwm.cli doctor
Extract the complete Linux tarball. From its application folder:
./Start\ ArWen.sh --python ~/.local/share/arwen/venvs/2.7.2/bin/python
If your distribution does not include Python's venv module, install its venv
package first; Ubuntu provides python3-venv.
The Linux launchers open the connected GUI and TUI. Use
Start ArWen Terminal.sh for the terminal alone. After activating a Python
environment, gpuwm tui also opens the terminal.
Settings and run caches live outside the application folder. Keep the application
files and notices together when moving or updating the desktop.
GPU requirements and forecast data
The normal desktop installation above already includes the GPU dependencies.
Local forecasting requires a compatible NVIDIA GPU and driver. A card's VRAM
capacity alone does not establish driver or CUDA compatibility.
For a manual Python installation on a supported CUDA 13 GPU and driver, replace
all-cu12 with all-cu13 in the installation command. Install only one CuPy/CUDA major in each environment.
A driver reporting CUDA 13 support can also run CUDA 12 applications; that
display does not require switching a working CUDA 12 installation. See
NVIDIA's compatibility guidance.
gpuwm doctor reports each remedy as a command or a # comment explaining
the manual step.
The GPU extra installs CuPy and the required user-space NVIDIA CUDA components
through their dependency packages. It does not install Python or the NVIDIA
device driver. Install one CuPy/CUDA major per environment. See the
CuPy installation guide and
ArWen hardware guidance.
Most scientific lookup data arrives with the automatically installed
gpuwm-data package. gpuwm fetch-tables obtains and hash-checks two additional
Thompson tables, about 314 MiB combined. Geography and forecast inputs are
separate: configure an existing geography installation or use gpuwm fetch-geog.
ERA5 requires the user's CDS configuration and dataset access. Remote operation
requires an SSH client and a configured, reachable forecast computer.
Local forecast integration runs on CUDA; it has no CPU fallback. The desktop,
terminal, native weather processing, and remote-control workflows can run on a
computer without a local CUDA installation.
Only an intentionally viewer-only or remote-control installation should use
gpuwm[render]==2.7.2 without a GPU extra. It cannot execute local forecasts.
Work with weather
- Explore: choose a supported source, field, area, and valid time; load a
weather map and play available UTC frames.
- Create forecast: start from an area, an Explore map, a saved configuration,
or a cyclone setup. Choose the forecast computer and inputs, review the
resolved physics and memory requirements, then launch.
- My forecasts: return to active or saved runs, inspect domains and output
times, view native fields and plots, and play the forecast history.
- Terminal and CLI: use
gpuwm tui for an interactive workspace or the
command interfaces for scripts and automation.
GFS, HRRR, and ERA5 workflows are included, with ERA5 member selection and
cyclone-follow setup among the 2.7 features. The installed source catalog is
available through gpuwm sources --json. Forecast-input support and Explore
preview support are separate; some registered forcing sources do not yet have
an Explore preview route.
For a configuration already prepared for your computer and inputs:
gpuwm go forecast.toml --dry-run
gpuwm go forecast.toml
The first command reviews the route; the second executes it. See the
CLI manual
and TUI manual
for the complete workflows.
Integrate ArWen into another application
The integration guide
and downloadable kit
describe the CLI, run-plan documents, catalogs, and companion bridge boundaries.
The kit contains an example subprocess client and tests. It is a documented
integration surface, not a separate simulation engine or a replacement for
runtime validation.
Use the installed catalogs and validated plans when building another interface.
Preserve request identity, selected source/time/domain, cancellation, and the
distinction between a preview and an executing forecast.
Science, compatibility, and current limits
ArWen independently implements a WRF-ARW-class regional atmospheric model and
WRF-derived physics on the GPU. Its numerical comparisons and qualification
apply to documented configurations and test cases. They do not establish
universal equivalence with WRF or validate every combination of physics,
input dataset, and hardware. Read the
verification record,
physics documentation,
and 2.7 changes.
- Checkpoints: 2.7 writes format 6. Format-5 checkpoints from older releases
and previews are not compatible. Finish those runs with the version that
created them, or start again from the original configuration and inputs.
- Physics admission: some Noah-MP configurations currently refuse during
memory estimation. The refusal does not silently replace the selected physics.
- Playback: the first pass may wait while remote frames enter the local
cache. Startup compilation and input preparation also affect reported overall
simulation speed.
- Known interface issues: some preview sources remain unavailable, exported
dateline-crossing outlines can show a seam, and a background compact-store
worker can report an error during the forecast-completion transition. The
release qualification documents the retained limits.
ArWen is research and educational software. Use official meteorological services
for forecasts and safety warnings. The project is not affiliated with or endorsed
by NCAR or UCAR.
Report an issue
Include the version, platform, what you attempted, and the relevant error.
gpuwm report RUN_DIRECTORY --output diagnostics.zip collects a diagnostic
report with recognized sensitive patterns redacted. Review it before sharing:
raw copied logs can contain local paths, usernames, hosts, and configuration
details, and no redaction tool guarantees anonymity. Never post credential files
or private keys. See
reporting a problem.
Development and licensing
Development combines human direction, AI-assisted implementation, and numerical
and runtime verification. The source, scientific provenance, tests, and release
qualification records are available for inspection.
For a developer installation from a source checkout, use bash install.sh on
Linux or powershell -File install.ps1 on Windows. Source installations build
the native components and need the corresponding build tools. The explicit
bash install.sh invocation also works when an extracted source archive has
lost executable permission bits; use it if ./install.sh reports
Permission denied.
The engine is licensed under the Apache License 2.0.
The desktop application and its dependencies carry their own licenses and
notices in the desktop archives. Third-party code, tables, and datasets retain
their respective terms; see NOTICE
and scientific provenance.