Severe-weather workstation for Windows. Decodes NEXRAD Level II radar from raw base data — live or replayed from the archive — and GPU-renders it over local, fully style-controlled vector basemaps, with SPC outlooks, watches, warnings, and storm reports layered on top.
Anvil decodes NEXRAD Level II radar itself. It reads the raw .V06 volume — Message 31 radials,
per-moment data blocks, VCP and elevation tables — and renders every gate on the GPU. No server-side
rendering, no image tiles. It draws seven products (reflectivity on the standard NWS dBZ scale;
velocity, storm-relative velocity, correlation coefficient, differential reflectivity, specific
differential phase, and spectrum width on ramps built for the app), dealiases velocity with a validated
port of Py-ART's region-based algorithm, and derives storm motion automatically from a full-volume VAD
wind profile. Elevation cuts, SAILS re-scans, and split-cut Doppler companions all resolve from the
volume's own tables. Curated Doppler On Wheels mobile-radar frames render through the same pipeline.
You can run it live or replay history. The live loop pulls recent volumes from the AWS archive and stitches in a near-real-time frame from the chunks bucket, cutting the usual ~10-minute archive latency to a minute or two. The Past Event Viewer plays any site and date back through the 1990s through the exact same pipeline — scrub it, loop it, and read the decoded value under the cursor off the Inspector.
It overlays the severe-weather picture on top. SPC convective and fire outlooks (Days 1–8, with significant-area hatching), tornado and severe-thunderstorm watches, storm-based warning polygons from the authoritative NWS CAP feed, and SPC storm reports as verification dots — all keyed to the right forecast window, so a replayed event lines up with the outlook that was in effect and the reports that verified it.
The basemap is local and fully yours. Instead of a tile service, Anvil reads one offline PMTiles archive with style JSON you control, so a cartography change is a file edit and panning costs nothing. Five styles ship with the app, and a single-state or CONUS isolation mode masks everything else away for a clean view. If you'd rather not host tens of gigabytes, those same five styles will render from an online tile source instead — they're tied to the Protomaps schema, not to the file, so it's one setting and the map looks identical either way; offline stays the default. It's a Windows desktop app (WinUI 3, packaged MSIX) in active development, with the UI mid-rebuild — several capabilities live in the view models ahead of the controls that expose them.
Not for operational use; rely on official NWS products for any safety-of-life decision.
| OS | Windows 10 1809+ (Windows 11 recommended) |
| Build | .NET 8, Windows App SDK 2.1.3, Visual Studio 2022 with the Windows App SDK workload |
| Runtime | WebView2 (preinstalled on Windows 11; Evergreen runtime on Windows 10) |
| Basemap | A local PMTiles archive, or an online tile source — see docs/setup.md |
dotnet build Anvil.App/Anvil.App.csproj -c Debug -p:Platform=x64 -p:RuntimeIdentifier=win-x64The platform must be explicit — plain AnyCPU fails during MSIX packaging. Anvil is packaged as MSIX and
depends on package identity for its local caches, so run it from Visual Studio with F5 (which deploys
the package); the loose .exe throws. Anvil ships without a basemap, and without one the map is black
while every overlay still draws. docs/setup.md covers building the archive, where
to put it, the online-tiles alternative, and the rest of the build and test recipes.
Four projects, with the boundary enforced by target framework: Anvil.Core (net8.0, no Windows
dependency — models, services, view models), Anvil.App (net8.0-windows — the WinUI 3 shell and the
web layer), Anvil.Tests, and tools/TiltCheck. The map is MapLibre GL JS in
a single WebView2, because WebGL rendering can't happen in C#; that web layer is kept narrow, and
everything that can be C# is. CLAUDE.md is the working map of the codebase — where things
live, how to build, and the gotchas — and docs/ holds one deep-reference file per area (radar tilts,
velocity dealiasing, the live frame path, product history, decode validation, the replay and DOW
viewers).
| Data | Source |
|---|---|
| NEXRAD Level II | Unidata's archive and chunks buckets on AWS |
| Outlooks, watches, warnings, storm reports | NOAA/NWS Storm Prediction Center and NWS map/alert services |
| Basemap | Protomaps — a local archive or the hosted API — © OpenStreetMap contributors |
The bundled DOW sample comes from NSF NCAR EOL by way of the open-radar-data archive; any .dow.json
you add redistributes research data, so use openly licensed archives and carry the citation. Built with
MapLibre GL JS, PMTiles, the nexrad-level-2-data decoder,
seek-bzip, and SharpCompress.
Anvil is an independent project — not affiliated with, endorsed by, or supported by NOAA, the National Weather Service, Unidata, or NSF NCAR.
Anvil is self-taught work. I have no formal background in meteorology, radar engineering, or software development, so expect some non-standard choices. Corrections are welcome, particularly on the meteorology and the Level II decoding.
AGPL-3.0. Derivative work must be released under the same license.