Comparison of MHD modeled solar wind speeds at the location of the three spacecraft (PSP, Earth, and Stereo-A (STA)) with the interval defined by each PSP perihelia pass (1-4). In each panel, speeds from 200 to 800 km s⁻¹ are shown in the rainbow spectrum from blue to red, using the same transitions as in Fig. 2’s colour bar. The orbit of each spacecraft is shown by the white curve and the location of the HCS is marked by the red contour (B_r = 0).