Tropical cyclones in the east Atlantic often form in regions with marginal SST, but move towards warmer water. They also usually form in favorable easterly or weak westerly shear environments, but often move towards regions with increasing westerly shear along their westward track. Thus, the typical Atlantic storm has an increasingly favorable thermodynamic environment, but decreasingly favorable dynamic environment as it evolves. The intensity of these TCs is usually well below their maximum potential intensity (MPI), and the intensity changes are strongly influenced by the evolution of the vertical shear. In contrast, east Pacific TCs typically form in regions with high SST and high shear, and move towards colder water, but with lower shear as they intensify. In the latter stages of east Pacific TCs the storms are often close to their MPI, and so provide a sample to more directly study the MPI controls on TC intensity changes. This web page includes several examples of east Pacific TCs that reached their peak intensity as they moved towards cold water, but in very low shear environments.