Previous studies have demonstrated that buoyancy and wind shear play an important role in modulating turbulence organization in the convective boundary layer (CBL). Although transitional periods in the CBL have been studied using observations and numerical modeling, most previous studies have focused on statistical properties under steady-state forcings. In this study we investigate how turbulence organization reacts to unsteady surface forcing by running a suite of large eddy simulations with a temporally variable surface heat flux and a range of geostrophic wind values. For each simulation, a homogeneous surface heat flux ( \(Q_0\) ) of 0.05 \({{\text { K m s}}^{-1}}\) is imposed for 10 h to allow the flow to reach a quasi-steady state before \(Q_0\) is increased instantaneously to 0.30 \({{\text { K m s}}^{-1}}\) . At hour 13, \(Q_0\) is reduced back to 0.05 \({{\text { K m s}}^{-1}}\) . Mean geostrophic wind ranges from 6 \({{\text { m s}}^{-1}}\) to 15 \({{\text { m s}}^{-1}}\) and is held constant through each run. Using the roll factor, which is based on the rotational symmetry of the vertical velocity two-point correlation, and the ratio of integral length scales in the streamwise and spanwise directions, we find that large-scale convective structures transition from roll-like when \(Q_0\) is low to cell-like when \(Q_0\) is increased. Hysteresis is found in these structures as a function of \(-z_i / L\) and are found to vary from structures seen under stationary surface forcings at the same stability. These results demonstrate that CBL structures are not a function of \(-z_i/L\) alone during transition periods, but exhibit dependence on the temporal history of \(Q_0\) experienced by the CBL.
