The current convective instability has recently been proposed as a possible mechanism for generating large scale irregularities in the auroral F region, driven by weak field-aligned currents associated with the diffuse aurora and a plasma density gradient. In this report, we show that this instability can stabilize nonlinearly by generating linearly damped harmonics. An estimate of the saturated amplitudes shows good agreement with the available experimental data. In addition, with a northward plasma density gradient, the dominant nonlinear harmonic is in the northward direction, in agreement with DNA Wideband satellite observations.