The tenth named storm of the annual typhoon season, Ampil developed into a tropical depression east of Luzon on July 17.

The system gradually strengthened over the following days amid a marginally favorable environment and became a severe tropical storm late on July 19 as it moved northwest.

The system turned eastwards as it continued weakening over land, diminishing to a remnant low on July 25 and dissipating fully a day later over the Russian Far East.

Ampil produced gusty winds across the Ryukyu Islands from July 20 to 21, causing disruptions to transport and businesses.

From July 22 to 25, Ampil generated heavy rains across much of East and Northeast China, affecting more than 2.3 million people and causing record-breaking flooding within the watershed of the Songhua River.

[nb 1] A broad area of disturbed weather developed within the monsoon trough on July 15 roughly 1,215 km (755 mi) south-southeast of Okinawa.

[3][nb 2] The system initially moved east-northeastwards around a ridge near the Equator, while gradually organizing amid generally favorable upper-level wind patterns and high sea surface temperatures of 29–30 °C (84–86 °F).

[8] Intensification was slow as upper-level winds restricted outflow in Ampil's northern half, preventing thunderstorms from developing there.

[9] Later on July 19, the unfavorable upper-level winds diminished slightly and allowed thunderstorms to develop over Ampil's center of circulation, resulting in it becoming well-defined.

[3] Ampil then maintained this intensity for the next two days due to the limiting effect of surrounding dry air, while continuing to track northwestwards.

A lightning strike damaged the runway at Fukuoka Airport, forcing it to close for an hour and resulting in 70 flights being canceled.

[26] Ahead of Ampil on July 20, the Chinese National Meteorological Center issued a yellow alert, the third-highest rating on their warning system.

[33] As Ampil tracked further inland from July 22 to 25, it produced a large swath of heavy rain across East and Northeast China.