Abstract. Considerable controversy exists concerning the relative roles of the E- and F-regions in controlling irregularity formation in the mid-latitude ionosphere, largely because electric fields due to a plasma instability in one region may map to the other if the perpendicular scales are sufficiently large. In this paper we look at a particularly fortuitous data set in which both E- and F-region observations were made using incoherent scatter radar, GPS, lidar, and coherent scatter radar. In this event, a dense, patchy sporadic E layer was detected that exhibited type I (two-stream) coherent echoes while, at the same time, the F-layer plasma was highly structured with plasma drifts of hundreds of m/s. We examine this event in the context of a mesoscale traveling ionospheric disturbance. The data presentation will be followed by comparison with current theories for coupling between these two regions.