We discuss multi-instrument observations of the excitation and decay within a ~10 min interval of a convection pattern typical of lobe cells, centered at ~1230 MLT in the winter hemisphere. The plasma convection and its associated aurora were triggered by a rapid northward turning of the interplanetary magnetic field (IMF) monitored by near-Earth spacecraft. The IMF stayed northward oriented (Bx=-4 nT; By=2--3 nT; Bz=2--4 nT; clock angle=30¿--70¿) for 8 min, before rotating back south. The optical instruments recorded the activation of an east-west aligned auroral form near the latitude of the pre-existing cusp aurora at ~73¿ MLAT, which was followed by a smooth, 10-min long poleward advance at an average speed of 0.4 km s-1, reaching 75¿ MLAT at its most expanded phase. Simultaneous CUTLASS radar and local magnetic data confirm the occurrence of a large reconfiguration of plasma convection involving a change from antisunward to sunward flow components in the vicinity of the cusp, consistent with the presence of a lobe cell. ¿ 1999 American Geophysical Union