HRRR caps at f018, so beyond ~18 hours the map and path calculator
go blank. This plan scopes a GFS open-data ingest that runs
alongside HRRR to drive the 18-240 hour forecast window, with a
visible seam on the timeline where the resolution drops from 3 km
to 0.25°.
Scope: GFS 0.25° CONUS subset from AWS S3, four runs/day on the
standard cycle, chained fetch/score workers that mirror the HRRR
pipeline shape, per-source binary score files so HRRR and GFS stay
independent. ECMWF IFS HRES listed as a follow-up once GFS works.
