This is the name of the 8th tropical cyclone of the Northwestern Pacific season. The fact that it has a name shows it is at least at tropical storm strength, with winds currently blowing at 55 knots (that's force 10 to 11 on the Beaufort scale), but forecast to increase to 110 knots by next week. This strength would place Ma-on at category III on the Saffir-Simpson hurricane wind scale.
At the moment, Ma-on is more than 600 miles from any land and will not threaten any land, apart from Iwo Jima and Chi Chi Jima, for at least five days. JTWC (the Joint Typhoon Warning Center in Hawaii) specifically warns that the storm will not follow the most common scenario, namely of veering northeast and being swept away in a much weakened state by the mid-latitude airstream. Japan is currently experiencing a heatwave, with temperatures between 90 and 95F (32 to 35C). The set-up in the atmosphere which has brought this extreme heat will also permit Ma-on to approach Japan unrestrained, and don't be surprised to hear of a category III typhoon (if not worse) making landfall in mainland Japan next week.