Setup. After DA cycling (12–15 Z, 4 hourly 3D-Var cycles),
the pipeline releases a free forecast starting at 15 Z (valid to 12 Z+1, 21 h)
on d01→d02→d03 via ndown. Both branches — control and
radar-cycled — share the same GFS 12Z lineage (fair baseline: no cold start,
no spin-up mixing).
The event was a weak afternoon convective episode, 16–21 Z. The d03 box (centred −21.99°, −41.31°) landed in a region with only 10 rain-gauge stations — station scores at d03 are empty; the signal lives on d02 and in the MODE/object-based metrics.
