This paper discusses a recently published series of 12 successive images of the northern auroral oval obtained by the University of Iowa's auroral imager on DE 1 during a substorm on November 8, 1981. The images showed a sudden (within <12 min) thickening and poleward expansion of the midnight sector of the oval that occurred at the ''maximum epoch'' of the substorm, i.e., as auroral zone bays reached their peaks and began to subside about 90 min after the expansive phase onset. We propose that this was the auroral manifestation of the poleward leap of the auroral electrojet that has been reported on many occasions to coincide with thickening of the plasma sheet in the outer magnetotail (beyond ~15 RE) late in a substorm. The plasma sheet thickening is thought to be associated with a tailward retreat of the substorm magnetic neutral line. We note evidence that the neutral line's tailward retreat influences auroral currents and particle precipitation even at low auroral latitudes. Modifications of the present auroral substorm model are suggested.