Across the Philippines, heavy rains triggered mudslides that claimed 16 lives and forced over 20,000 others to be evacuated.

Due to the storm, reservoir levels in Okinawa on the island rose from only 35% to over 80% of its capacity and crop damage amounted to $7.4 million USD.

[1] On the next day, the Japan Meteorological Agency (JMA) designated the system a tropical depression.

[2][nb 1] Wind shear began to diminish on July 22, coinciding with falling pressures at Yap and increased convective activity.

[1] On July 24, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) also started watching the storm and assigned it the local name Ising.

[4] A rapid increase in convection prompted both the JTWC and JMA to upgrade the depression into Tropical Storm Caitlin the same day.

[5][nb 2] Tropical Storm Caitlin tracked west-northwestward until July 24, when a semi-permanent subtropical ridge weakened near 130°E, which caused the tropical storm to make a sharp northward turn; this turn was forecast well in advance by the Navy Operational Global Prediction System.

[2] Satellite imagery depicted a cloud-filled eye,[1] and midday on July 25, the JTWC upgraded Caitlin into a typhoon,[7] with the JMA following suit that evening.

[1] At the time of the upgrade, Typhoon Caitlin was located around 440 km (275 mi) south of Okinawa.

The typhoon passed 110 km (70 mi) west of Kadena Air Base at 15:32 UTC on July 27.

[1] Meanwhile, the JMA estimated a peak intensity of 145 km/h (90 mph) and a minimum barometric pressure of 940 mbar (28 inHg).

[2] After passing Okinawa, the typhoon tracked north-northeastward around the periphery of a broad subtropical ridge.

On July 29, Caitlin, while weakening, accelerated towards the northeast through the Korea Strait, and gradually transitioned into a typhoon force extratropical low as it moved into the Sea of Japan.

[2] The typhoon enhanced the monsoon across the northern Philippines, and caused rainfall to areas already deluged by prior floods.

[1] The typhoon dropped heavy rainfall across much of the Japanese archipelago, as far south as Okinawa and as far north as Chūbu region.

[18] Twenty-three people were wounded in Nagasaki Prefecture, including one who suffered a spinal cord injury due to strong winds.

[29] Prior to affecting South Korea, typhoon warnings were posted for the entire country.