We report a recurrent convection signature observed in the E region ionosphere within ~2 hours of the dusk meridian by the SABRE radar facility. In a typical event, the irregularity drift speed in the SABRE field of view is seen to increase from about 300 m s-1 to of the order of 1 km s-1 in the space of about 10 min. The speed subsequently remains at the enhanced level for 10 min or longer before declining as rapidly as its onset. The total event duration ranges between 30 min and 1 hour. As the irregularity drift speed increases the direction of the drift velocity changes, rotating poleward. At the same time, the radar backscatter power decreases. The onset of the drift speed enhancement crosses the SABRE field of view as a front moving from east to west. Detailed study of individual events indicates that the events are associated with increases in the ‖AL‖ index and with the injection of energetic particle into geosynchronous orbit. We thus suggest that the events are part of the magnetospheric response to the onset of a geomagnetic substorm. However, while each event appears to be associated with a substorm onset, not every substorm onset is associated with an event, at least not at SABRE. We estimate the speed at which the substorm-initiated ionospheric flow enhancement moves from the nightside to be 1--4 km s-1, a figure that is consistent with the rate at which the drift velocity front crosses the SABRE field of view. Although the front is associated with a rotation in the drift velocity, we see little evidence of strong vertical vorticity as the front passes. However, shears in the flow to develop subsequently which seem likely to correspond to field-aligned current. Although associated with substorm onset, we argue that these events are distinct from westward traveling surges and appear to differ from the mid-latitude phenomenon known as subauroral ion drifts. We thus call this new-found signature a substorm associated radar auroral surge or SARAS event. ¿ American Geophysical Union 1992