BTW, these are ensemble models for the NOAA GFS (FV3) and CMC GDPS models. Ensemble models are where the starting conditions of weather simulation is perturbed slightly and the simulations re-solved. They do this 20-odd times and you end up with 20-odd tracks. So for both GFS and GDPS there will give 40-odd paths.

Sometimes, it can be interesting how the cluster of GFS tracks may differ from the GDPS tracks.