Abstract
The role of static stability (σ) is diagnosed for an intense extratropical cyclone that developed over the central United States during 9–11 January 1975. Results indicate that minimum σ, values occurred in the lower troposphere at 0000 UTC 10 January 1975, during the period of slow cyclone development, and then increased as rapid development proceeded. Further, the upward advection of smaller static stabilities in the cyclone area, a forcing process in the height tendency equation, resulted in a significant reduction of height falls attributed to vorticity advection, thermal advection, and latent heat release.
