Normalize longitudes to -180..180 and remove strict bounds so velocity particles render globally

Use jsDelivr Leaflet-Velocity 1.8.0 and align particle options to working wind demo (red gradient)

Make visualization wind-like particles in red

Animate wave arrows; use height+period for per-arrow styling; add gribplayground Arctic fetcher (no pygrib)

Use wave period to derive group velocity magnitude for U/V grid; tune velocity layer options for visibility

Overlay sparse arrow polylines alongside velocity layer for immediate visual feedback

Fix 500 on /data/points: sanitize NaN/Inf and numpy types; also sanitize velocity fallback

Velocity rendering: ensure lon ascending, sanity-check nonzero data, tune particle density/scale

Frontend: robust handling of velocity payloads, add status text, final fallback to points; Backend: fall back to points when UV grid is empty/trivial

UI: make control overlay clickable by adding z-index

Sanitize velocity JSON: replace NaN/Inf with 0.0 and clamp values to avoid JSON errors

Serve Leaflet map as standalone route (/ and /map); move Gradio UI to /ui; fix CSS pointer-events for control

Fix SyntaxError: avoid f-string in embedded HTML; normalize JS braces; ensure Gradio mount

Add Leaflet velocity wave visualizer: FastAPI+Gradio app, NOAA WW3 puller, endpoints, Dockerfile, requirements