We examine the mean meridional flow in the summer upper mesosphere using data from the Poker Flat MST radar and all other available stations. The observed mean flow is equatorward at about 10--15 ms-1 near 60¿N, about an order of magnitude larger than expected from numerical model results. The Rayleigh friction coefficient required to balance the coriolis torque associated with this flow is about 4 days-1, about ten times larger than values currently used in numerical models.