Overnight, Hinnamnor cleared a small eye along with a well-defined CDO, and intensified into a high-end Category 4-equivalent super typhoon.

An increasingly hostile environment caused it to lose its convective features the night of September 1, weakening it down to a Category 1-equivalent typhoon.

Beginning to weaken for the final time on September 5, the storm made landfall late that day as a Category 2-equivalent typhoon and began extratropical transition.

Heavy rainfall affected northern districts in Taiwan, and a man died in the Philippines due to Hinnamnor's flooding.

Hinnamnor made landfall just southeast of Geoje in South Korea, knocking out power for tens of thousands of homes.

[1][2][3][4][excessive citations] On August 27, the Joint Typhoon Warning Center (JTWC)[nb 2] began monitoring a tropical disturbance about 500 nautical miles (925 km; 575 mi) east-southeast of Iwo Jima.

[6] Satellite images indicated that the north and southeast areas were accompanied by deep convection wrapping into the low-level center.

[6][7] At around 00:00 UTC on August 28, the Japan Meteorological Agency (JMA)[nb 3] began monitoring a tropical depression that had developed in the Philippine Sea.

[10][11] A central dense overcast feature and prominent spiral banding, noting its obscure low-level circulation center.

[14] At 09:00 UTC, the JTWC upgraded Hinnamnor to a Category 1-equivalent typhoon, with maximum sustained winds of 75 knots (140 km/h; 85 mph).

[19] Overnight, Hinnamnor cleared out a small, round eye, and strengthened into a high-end category 4-equivalent super typhoon.

[23] As it headed towards the Ryukyu Islands, Hinnamnor proceeded to reorganize on satellite with an intense CDO forming along with a larger eye.

[24] It re-intensified back to a Category 5-equivalent super typhoon on September 1,[25] and, at the same time, Tropical Depression 13W (Gardo) embedded into the wind field with Hinnamnor.

[26] Hinnamnor weakened to Category 4-equivalent super typhoon by 09:00 UTC due to elongation of the convective core and cooler sea surface temperatures.

[29] At 09:00 UTC, Hinnamnor further weakened into a Category 1-equivalent typhoon as it finally began to move north-northwest into the East China Sea.

[34] Multispectral animated satellite imagery revealed a 10 nautical miles (19 km; 12 mi) surrounded eye around a spiral banding.

[39] At 03:00 UTC the next day, the JTWC issued their final warning on the system as it began its transition into an extratropical cyclone, with its frontal structure.

[43][44] An official at the JMA called for "strict vigilance" against Hinnamnor, and recommended those move to sturdy buildings and shelters as the typhoon approached.

[52] South Korean President Yoon Suk-yeol ordered Interior Minister Lee Sang-Min to come up with the highest response measures for Hinnamnor.

[55] Preliminary weather advisories were issued in southern areas of the country, including the cities of Gwangju, Busan, Daegu, and Ulsan on the September 4.

Prime Minister Han Duck-soo called for schools to close down or switch to distance education until on September 5.

[60] Eight flights, two domestic and six international, and 106 ferry services on 12 routes were cancelled,[61] as well as school closures in several districts.

In Watanagi Village, rainfall of up to 64 mm (2.5 in) per hour fell; the highest of such observation during the month in the past decade.

[77] Hinnamnor also left 70 vessels on 50 sea routes grounded, 251 flights at 12 airports cancelled, and 354 train schedules suspended or adjusted.