page_title: Typhoon Percy (1990)
section_title: Meteorological history
hierarchical_section_title: Typhoon Percy (1990) / Meteorological history
caption_attribution_description: Saffir-Simpson Hurricane ScaleTDTS12345 English: Typhoon Percy 1990 track. Uses the color scheme from the Saffir-Simpson Hurricane Scale.
context_page_description: Typhoon Percy, known in the Philippines as Typhoon Klaring, was the third tropical cyclone to affect the country in 1990. The tenth tropical cyclone, sixth tropical storm, and third typhoon of the 1990 Pacific typhoon season, Typhoon Percy originated from an area of disturbed weather spawned by the Western Pacific monsoon trough on June 20. That same day, the disturbance was classified as a tropical depression as it slowly organized and on June 21, the depression obtained tropical storm intensity. After initially tracking westward, Percy turned towards the southwest while slowly deepening. During this time, Percy affected several of the Carolina Islands. Thirty homes were damaged and airline services were halted in and out of Yap. Farther south-southwest, seven homes were destroyed on the Ngulu Atoll. Furthermore, one boy was killed on Koror, where numerous homes lost their roofs and communication lines were downed. Percy then turned back to the west-northwest and became a typhoon on June 23. It then began to deepen at a faster rate, with Percy attaining its maximum intensity of 145 km/h on June 25.
context_section_description: Typhoon Percy originated from the eastern end of the Western Pacific monsoon trough that spawned an area of disturbed weather that was first noted by the Joint Typhoon Warning Center (JTWC) on the morning of June 20. Satellite imagery showed signs of a well-defined low-level circulation and the disturbance was situated along with persistent convection, and the disturbance was situated in a weakly divergent environment aloft. On the same day, the Japan Meteorological Agency (JMA) upgraded the system into a tropical depression. The system gradually became more organized as its outflow expanded, and following a marked increase in convection, the JTWC issued a Tropical Cyclone Formation Alert on the system at 03:00 UTC on June 21. Following a ship report of winds of 65 km/h (40 mph), both the JTWC and JMA upgraded the system into Tropical Storm Percy. After initially tracking westward, Percy turned and tracked southwestward for 36 hours, a move predicted by tropical cyclone forecast models but not foreseen by the JTWC. Meanwhile, the storm slowly intensified, aided by the development of an anticyclone aloft. Tracking west-northwestward around another upper-level anticyclone that was previously following Typhoon Ofelia and later merged with a subtropical ridge to its north, Percy was upgraded into a severe tropical storm on June 22 by the JMA. Following the development of an outflow channel to its south, hints of an eye became visible on satellite imagery. Based on a Dvorak classification of T4.0/120 km/h (75 mph), the JTWC upgraded Percy into a typhoon on the evening of June 23, with the JMA subsequently following suit.
  After moving away from the Caroline Islands, the typhoon began to intensify at a faster clip as an outflow channel to its north opened, even though the eye was initially ragged. On the evening of June 24, the JTWC raised the intensity of the system to 200 km/h (125 mph). Early on the next day, the JTWC estimated that Ofelia obtained its peak intensity of 210 km/h (130 mph); the basis for the estimate was a Dvorak estimate of T6.0 and a clear eye. Meanwhile, the JMA reported that Percy attained its maximum intensity of 145 km/h (90 mph) and a minimum barometric pressure of 960 mbar (28.3 inHg). Increased vertical wind shear took toll on the storm, and by June 27, the JTWC dropped the intensity of the storm to 175 km/h (110 mph) as the storm passed over northeastern Luzon. Overland, the storm weakened  slightly, but remained a typhoon upon entering the South China Sea. Both computer models and the JTWC expected Percy to begin recurvature; however, the subtropical ridge did not weaken as expected and Percy continued west-northwest instead. At 00:00 UTC on June 29, the JMA downgraded Percy to a severe tropical storm, although the JTWC suggested that Percy was still a typhoon at the time. Shortly thereafter, Percy moved onshore around 130 km (80 mi) southwest of Xiamen.  At 06:00 UTC, the JTWC downgraded Percy into a tropical storm, noting that the storm had become less organized. By June 30, both the JTWC and JMA had ceased tracking the system, which had dissipated inland.
caption: Map plotting the track and the intensity of the storm, according to the Saffir–Simpson scale
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