Continuing generally toward the west-northwest under steering currents from a mid-level ridge to its north, Nepartak maintained its windspeeds throughout the day. With an improving appearance on satellite imagery, however, the storm gained some additional strength, and the JTWC estimated 25W to have attained its first peak intensity with maximum 1‑minute sustained winds of 140 km/h (85 mph) at 0000 UTC on November 16.[1] Later that day, the JMA determined Nepartak to have reached maximum 10-minute winds of 120 km/h (75 mph), placing it at typhoon status. The cyclonic envelope began to ingest dry air from its surroundings, and convection began to wane, leading to slight weakening as the storm approached the island of Hainan.