Sub-auroral polarisation streams (SAPSs) are very fast plasma flows that occur at mid-latitudes, which can affect the atmosphere. In this paper, we use four ground-based radars to obtain a wide coverage of SAPSs that occurred over the USA, along with interferometer cameras in Virginia and Massachusetts to measure winds. The winds are strongly affected but in different ways, implying that the balance forces on the atmosphere is strongly dependent on proximity to the disturbance.