That was the closest that I have ever observed multiple tropical cyclogenesis events. (realclimate.org)
Why would the QBO, an ion wind, have an impact on cyclogenesis as William Gray reports? (realclimate.org)
I noted the data (independent data not depending on the identification of the intensity of tropical storms) indicates that there is no trend in all but one of the necessary conditions of cyclogenesis (wind shear, large scale vorticity and etc: see Hoyos et al. 2006) and that these parameters change only on interannual time scales. (realclimate.org)