A blue Moon can refer to either the second full moon in a calendar month or, more commonly, it means the first moon of two in a season that has four moons. The reason why this particular moon is a blue Moon is that it is the second full moon in August.
A tropical cyclone is a compact area of swirling winds surrounding a central region of low atmospheric pressure. About 85 of these occur annually over the warm tropical oceans. About half develop into a hurricane in Atlantic and eastern North Pacific or a typhoon in the western South Pacific.