[7] During July 2, the Japan Meteorological Agency started to monitor a broad tropical depression that had developed about 780 km (485 mi) to the southeast of Yap State.

[9] During that day as the depression intensified as it moved north-westwards in a weak steering environment, while deep atmospheric convection started to wrap into the system's consolidating low level circulation centre.

[10][11] Early on July 3, the United States Joint Typhoon Warning Center initiated advisories on the system and classified it as Tropical Depression 02W.

[8][12] The naming of Nepartak brought to an end a record 199 day period without a tropical storm within the Western North Pacific basin.

[13][14] After being named, Nerpartak started to accelerate north-westwards, as a subtropical ridge to the north of the system, became better established and acted as the dominant steering mechanism.

[15] Over the next couple of days the system gradually intensified further as its upper level outflow improved, as a TUTT cell positioned to the north of Nepartak propagated westwards.

[8][16] Thus, around 12:00 UTC, the JMA upgraded it to a severe tropical storm, and the system developed a large central dense overcast (CDO) with tightly curved convective banding.

[8][17] Both the JMA and the JTWC upgraded Nepartak to a typhoon early the next day, and afterwards the system underwent a period of rapid deepening.

[18][19] The system entered the Philippine Area of Responsibility approximately at 06:00 UTC (14:00 PHT), upon which PAGASA assigned it the local name Butchoy.

[22] Featuring a distinct eye, Nepartak reached its peak intensity at around 06:00 UTC, about 835 km (519 mi) east-southeast of Taitung, Taiwan.

[8] Maintaining peak intensity for a day, Nepartak started to slow down and weaken on July 7, owing to the topography of Taiwan inhibiting the inflow on the western side of the low-level circulation.

[8][31] On July 9, immediately before the JMA further downgraded Nepartak to a tropical storm, the system made landfall over Shishi, Fujian at 05:45 UTC (13:45 CST).

[8] On July 6, the Central Weather Bureau raised land and sea warnings for the entirety of Taiwan, and forecast torrential rain for 14 counties and the capital city of Taipei during the typhoon's passage.

[34] The Government of Taiwan placed 35,817 military personnel—of which roughly 3,000 were deployed[35]—along with 3,409 vehicles and 119 inflatable boats, on standby for relief efforts in conjunction with Typhoon Nepartak.

[46] Officials across multiple provinces in East China feared that the storm would worsen the ongoing floods that had already claimed at least 186 lives.

[49] Across coastal Fujian, approximately 33,000 fishing boats returned to port[50] and 35,000 people working along the coast were urged to evacuate inland.

[51] Residents across the Ryukyu Islands—a Japanese archipelago extending south-southwest from the mainland toward Taiwan—were alerted of potentially dangerous conditions beginning on July 5.

Meteorologists in the nation also advised that the typhoon would enhance the local monsoon, bringing rain and thunderstorms to many areas in the Northern part of the Philippine islands.

[56] The national government also suspended work in Metro Manila in the afternoon of July 8 owing to inclement weather caused by the typhoon.

One of the wealthiest people in Taiwan, Hon Hai Precision Industry Chairman Terry Gou, provided NT$10 million (US$310,100) for reconstruction efforts.

[65] Taiwan's Council of Agriculture pledged to provided financial assistance to farmers in Taitung, Pingtung, and Kaohsiung counties.