FAQ and glossary
Questions
Is it free? Is there an account? Yes, and no. HookEcho is open source under the MIT licence. There’s no account, no subscription and no telemetry — the app talks to the public NOAA and National Weather Service feeds directly from your machine.
What’s a hook echo? The signature the app is named after. A supercell’s rotating updraft wraps precipitation around itself, and on reflectivity that wrap draws a hook curling off the back-right of the storm. It was one of the first radar signatures ever tied to tornadoes, and it’s still one of the first things a forecaster looks for.
Where does the data come from? NEXRAD Level 2 and Level 3 from the radar network, MRMS for the national mosaic and gridded products, HRRR/NAM/RAP for the model layers, and the NWS for warnings, forecasts and storm reports. All of it public, all of it free.
How far back does the archive go? June 1991. Any archived storm loads the same way the live one does. Products that didn’t exist yet — CC and ZDR before the dual-pol upgrade around 2012 — aren’t there for old events.
Is the future radar real? No, and the app says so the whole time it’s on. HRRR future radar, forecast rotation tracks and smoke are model output, and they carry a banner for as long as they’re drawn.
Do I need an API key? Not for the weather. A couple of optional basemaps use commercial tile services and want their own key; a layer that needs one stays empty and says so rather than nagging. Keys go in Settings and stay on your machine.
Things that look broken
Nothing loads. The app talks to NOAA and the NWS directly, so this is
usually the network. --status prints a per-feed report from the terminal.
The times look wrong. Radar times read in the selected radar’s local time — not yours and not Zulu — so a Texas pane and an Oklahoma pane can differ side by side. Settings → Units switches everything to UTC.
It’s slow. Lower the 3D quality preset, turn off the animated wind particles, and use fewer panes. On a phone, close station cards you aren’t reading.
The disk is filling up. Settings → Storage lists every cache against its cap, with clear and open buttons. Nothing cached is irreplaceable.
Still stuck? Open an issue with the site, the product and the time you were looking at — that’s usually enough to replay it.
Glossary
Every radar word has its own page now, with the related ones linked from it:
CAPE, CC (correlation coefficient), dBZ, Dealiasing, Dual-pol, Level 2 / Level 3, MESH, MRMS, NEXRAD, Reflectivity (Z), SRH (storm-relative helicity), Storm-relative velocity, TDS (tornado debris signature), Tilt, VCP, Velocity (V), VIL, ZDR (differential reflectivity), and hook echo itself.