The Structure and Evolution of a Simulated Midlatitude Cyclone over Land

Abstract

Abstract Using output from a mesoscale model simulation, this paper describes the evolution of the three-dimensional temperature and humidity structures of an intense cyclone that developed over the eastern half of the United States during 14–16 December 1987. Some specific findings include the following. • The occlusion process at the surface appeared similar to the classical paradigm, with the cold front catching up with the warm front. Aloft, a warm-type occlusion structure formed as an upper baroclinic zone merged with the surface-based occluded front. • The frontogenesis associated with the cold and warm fronts was initially continuous, but as the system evolved, a break in the frontogenesis along the northern section of the cold front developed. A single frontogenesis feature appeared to support both the warm and occluded fronts. • A quasi-linear region of convective activity was observed in advance of the surface cold front. This convective line was associated with an upper-level humidity front, wh...