Numerical Simulation of Tropical Cyclogenesis From a Long-lived Easterly Wave

The weather research and forecasting (WRF-ARW) model is used to perform a numerical simulation of the evolution of a long-lived African easterly wave (AEW) and its transition to tropical cyclone (TC) Ernesto (2006). The objective of the simulation is to obtain a high resolution physically consistent data set to examine the processes that help in wave maintenance and TC genesis.

Salient results of this simulation include:

1) Wave track, precipitation and TC intensity that closely match the observations.

2) Formation of a closed circulation within the larger scale wave at multiple levels several days prior to TC formation.

3) The vorticity budget for the wave shows that vortex stretching contributes the most to the process of wave maintenance and TC genesis for this case.