late on september 24, 2006, the joint typhoon warning center, noted that an area of convection, had persisted about 460 nm to the southeast of manila, in the philippines. the jtwc assessed the development of a significant tropical cyclone, as fair. this was because convection was beginning to flare up near a developing low level circulation center, the jtwc also noted that the disturbance had a broad circulation. early the next day both the japan meteorological agency and the philippine atmospheric, geophysical and astronomical services administration (pagasa) designated the tropical disturbance as a tropical depression with pagasa assigning the local name of tropical depression milenyo, to the depression. later that morning the jtwc reassessed the potential of the disturbance forming into a significant tropical cyclone within 24 hours as good, and issued a tropical cyclone formation alert on the developing disturbance. early that afternoon the jtwc started to issue advisories on the disturbance and designated it as tropical depression 18w. later that day the jtwc upgraded as the depression moved towards the west it was upgraded to a tropical storm by the jtwc. early on september 26 the jma also upgraded the depression to a tropical storm, and assigned the international name of xangsane.