Synergistic Interactions between an Upper-Level Jet Streak and Diabatic Processes that Influence the Development of a Low-Level Jet and a Secondary Coastal Cyclone

Abstract

Abstract A series of numerical simulations is presented for the February 1979 Presidents' Day cyclone in order to understand more fully the roles played by upper-level jet streaks the oceanic planetary boundary layer (PBL), and latent heat release in the development of a low-level jet (LU) and secondary cyclogenesis along the East Coast of the United States. Mesoscale model simulations with and without sensible and latent heating show that the diabatic processes, along with the jet streak circulation patterns, contribute to the enhancement of the low-level winds and the initial development of the coastal cyclone. However. none of the mechanisms acting alone is sufficient to yield a satisfactory simulation of the LIJ and secondary cyclogenesis. Furthermore, the model-based diagnostic analyses indicate that a synergistic interaction must exist among these processes to account for the substantial increase in the magnitude of the low-level winds and the decrease in the sea level pressure that mark the seconda...