After turning north and bypassing Kyushu, Gladys began to encounter significant wind shear, which caused weakening.

Across southern Japan, the storm dropped heavy rains, with rainfall totals in some areas exceeding 710 mm (28 in).

According to the National Police Agency, torrential rains caused 92 landslides, damaged 48 roads, and washed away four bridges.

The storm's unusually large wind field resulted in extremely heavy precipitation across South Korea, where at least 90 people were killed while 62 others were injured.

A weak low-pressure area then developed and over the next two days, the disturbance slowly organized[1] while tracking northwestward.

[3][nb 1] An increase in curved banding features prompted the JTWC to declare the system Tropical Depression 14W at 00:00 UTC on August 16.

[2] At the same time, the JMA upgraded the depression into a tropical storm,[5][nb 2] with the JTWC following suit that evening.

However, Gladys' large size prevented significant organization, with tropical storm force winds extending some 665 km (415 mi) from the center.

[3] Continuing to slowly intensify,[5] Gladys turned west,[2] contrast to forecasts of recurvature,[1] and tracked through the Ryukyu Islands.

[2] On August 18, the JMA estimated that the storm attained its peak velocity of 115 km/h (70 mph), which it would maintain for several days.

[3] Surface observations from the Amami Ōshima prompted the JTWC to upgrade Gladys to a typhoon early on August 21 while, at the time, it was located 165 km (105 mi) northeast of Okinawa.

[1][2] A passing trough to its north enhanced southerly wind shear, and that along with land interaction triggered rapid weakening.

The JTWC discontinued warnings at noon on August 23,[1] with the JMA classifying Gladys as a tropical depression the next day.

[3] Monsoon rains caused by Gladys prompted maximum weather alerts for nine major river valleys in the provinces of Tarlac, Pampanga, and Zambales, all previously affected by a volcanic eruption weeks earlier.

[8] Due to Gladys' large wind field,[2] the storm dropped heavy rainfall across much of the Japanese archipelago for several days.

[13] While passing south of Okinawa, the outer fringes of the storm dropped moderate to heavy rainfall across Tokushima Prefecture.

[21] Seven people were killed in Otsuki, two in traffic accidents and five motorists died when a landslide swept their vehicles off a highway.

[9] According to the National Police Agency, torrential rains caused 92 landslides, cut 48 roads and washed away four bridges.

[32] In Punsan, eight people were confirmed killed and one was rendered missing, with a man dying after he was struck by a falling steel ladder while the remainder drowned in waist-high floodwaters.

Just north off Pulsan, the storm's high winds forced a 950,000 kW (1,273,970 hp) nuclear reactor to shut down.