As we await the start of the monsoon, the water temperatures around us seem to be important. The Pacific is apparently undergoing a signficant shift to an El Nino. Here is the animation of the global sea surface temperatures and anomaly. This could supply plenty of moisture if the monsoon gets started and draws from here. The Gulf of Mexico and Caribbean are near normal temperatures. Not as strong a moisture source. Also, the cooler water temps in the Gulf and Caribbean, and the El Nino should hinder hurricane season in the east.
As we wait, perhaps this article on the North American Monsoon is helpful