Typhoon Robyn, known in the Philippines as Typhoon Openg, was a mid-season tropical cyclone that brushed Japan during August 1993. Typhoon Robyn originated from a near equatorial monsoon trough in the eastern Caroline Islands in late July. Tracking west-northwest, a tropical depression developed on August 1, and became a tropical storm the next day. Following an increase in organization, Robyn obtained typhoon intensity on August 5. The typhoon briefly tracked west before veering to the northwest while intensifying. On August 7, Robyn attained its peak intensity of , with a barometric pressure of . After passing through the Ryukyu Islands, Robyn skirted past western Kyushu on August 9 while steadily weakening. Midday on August 10, Robyn lost typhoon intensity over the Sea of Japan. The next day, the system was declared an extratropical cyclone.
In advance of the storm, 5,300 individuals were evacuated from Nagasaki Prefecture. Around 100 flights in and out of Kagoshima Airport were called off. Throughout Japan, nine people were killed, and fifty others were wounded. A total of 564 structures were destroyed, 80 homes were damaged, 220 houses were flooded, roads were cut in 15 locations, and two dikes were ruined. On the island of Kyushu, over 10,000 people fled their homes and around 285,000 households lost electricity. Damage in the country totaled ¥10.3 billion, equal to US$92.3 million. In South Korea, 45 people were killed and damage was estimated at US$86 million. The remnants of the storm also dropped rainfall across the Russian Far East.
Meteorological history
The sixth and final tropical cyclone of July, Robyn originated from a near equatorial monsoon trough in the eastern Caroline Islands. At 06:00 UTC on July 30, the Joint Typhoon Warning Center (JTWC) started watching the system as thunderstorm activity had persisted as the disturbance tracked west-northwest. On the afternoon on July 31, a Tropical Cyclone Formation Alert was issued, following reports from Hurricane Hunters that a low-level center was forming. At 06:00 UTC on August 1, the Japan Meteorological Agency (JMA) upgraded the system into a tropical depression. Based on Dvorak classifications of T1.5/, the JTWC followed suit several hours later. Both the JTWC and JMA upgraded the depression into Tropical Storm Robyn at 06:00 UTC on August 2, with the JTWC citing Dvorak estimates of T2.5/ as the reason for the upgrade. At the time of the upgrade, Robyn was located northwest of Chuuk.
Initially, Tropical Storm Robyn meandered erratically within a mesoscale convective system. At noon on August 3, the JMA upgraded Robyn into a severe tropical storm. Banding features increased in coverage that afternoon as the storm itself slowed down. Early on August 4, the JTWC estimated that Robyn attained typhoon intensity, although operationally, this was believed to have occurred 12 hours earlier, when Dvorak intensity estimates supported an intensity of . Robyn then began to cease all westward movement and instead took a dive south, only to turn north and later northwest. According to the JMA, Robyn leveled off in intensity for 30 hours, and did not become a typhoon until noon on August 5. Early on August 6, data from the JTWC suggested that Robyn entered a period of rapid deepening over 36 hours, ending winds of . The JMA disagrees, noting that only slight intensification occurred during this period. On August 7, the JMA estimated that Robyn attained its peak intensity of , with a barometric pressure of . Starting late on August 7, the JTWC estimated that Robyn began a weakening trend, although according to the JMA, Robyn maintained its intensity through August 8, with its pressure further dropping to After passing through the Ryukyu Island, Robyn skirted past western Kyushu on August 9 while steadily weakening. Midday on August 10, both the JTWC and JMA agreed that Robyn lost typhoon intensity over the Sea of Japan. The next day, both the JTWC and JMA classified the system as an extratropical cyclone.
Impact
Japan
Prior to the arrival of the typhoon, forecasters noted that up to of rain could fall in parts of northern Kyushu and Shikoku and compared the storm's potential destruction to Typhoon Mireille, which struck the nation two years earlier. In Nagasaki Prefecture, about 5,300 people were evacuated from their homes at the foot of the Mount Unzen volcano due to fear of landslides. Under the anticipation of rough weather, about 100 flights out of Kagoshima Airport were canceled, with airports in numerous other prefectures also suspending flights. The Kadena Air Base was evacuated at 03:00 UTC on August 8. Starting on August 9, all bullet train services between Hakata and Hiroshima were suspended.