The Enhancement of Cold-Front Temperature Contrast by Differential Cloud Cover

Abstract

The thermal impact of differential cloud shading across a cold front is evaluated briefly through conceptual, scaling, and numerical-modeling approaches. It is suggested that in summer the shading may enhance the boundary-layer average thermal contrast across the front by as much as 5 K for prolonged shading over the cold sector and with a dry surface in the warm sector. For short shading duration or wet surfaces along the warm sector, the thermal impact of shading reduces significantly. It is concluded that the shading effect may provide a pronounced contribution to frontogenesis for weak or moderate cold fronts.