熱帶氣旋形成警報
On August 16, a large area of low pressure centered about 335 km (210 mi) northwest of Okinawa began to show signs of possible tropical cyclogenesis. Initially, the storm's center was mostly cloud-free as subsidence from the mid-level low suppressed convective activity. Later on August 16, however, strong divergence moved into the region and allowed for showers and thunderstorms to form. Subsequently, the JTWC issued a Tropical Cyclone Formation Alert and later issued the first advisory on Tropical Depression 19W early on August 17.