Comparison of the standard correlation coefficients CC (pink) and weighted correlation coefficients wCC (blue) for nine solar wind parameters at rolling steps 1, 5, and 9 on the test set. The CC is calculated between the rolling predictions at the near-Earth grid point (r ≈ 215 R_s) and hourly OMNI observations. The wCC is calculated between the predictions and the MHD true values in the two-dimensional spatial domain. Each step corresponds to a forecast advance of 24 hr.