page_title: Typhoon Koppu
section_title: Meteorological history
hierarchical_section_title: Typhoon Koppu / Meteorological history
caption_attribution_description: English: Track map of Typhoon Koppu of the 2015 Pacific typhoon season. The points show the location of the storm at 6-hour intervals. The colour represents the storm's maximum sustained wind speeds as classified in the Saffir–Simpson scale (see below), and the shape of the data points represent the nature of the storm, according to the legend below. Saffir–Simpson scale Tropical depression≤38 mph≤62 km/h Category 3111–129 mph178–208 km/h Tropical storm39–73 mph63–118 km/h Category 4130–156 mph209–251 km/h Category 174–95 mph119–153 km/h Category 5≥157 mph≥252 km/h Category 296–110 mph154–177 km/h Unknown Storm type Tropical cyclone Subtropical cyclone Extratropical cyclone / Remnant low / Tropical disturbance / Monsoon depression
context_page_description: Typhoon Koppu, known in the Philippines as Typhoon Lando, was a powerful and devastating tropical cyclone that struck Luzon in October 2015. It was the twenty-fourth named storm and the fifteenth typhoon of the annual typhoon season. Similar to Goni earlier in the year, Koppu originated from a tropical disturbance east of the Mariana Islands on October 10. Moving briskly west, the system consolidated into a tropical depression the following day and further into a tropical storm on October 13. Situated over the warm waters of the Philippine Sea, Koppu quickly deepened. The storm reached its peak intensity on October 17 with ten-minute sustained winds of 185 km/h according to the Japan Meteorological Agency. The Joint Typhoon Warning Center assessed Koppu to have been a Category 4-equivalent super typhoon with one-minute sustained winds of 240 km/h. The storm subsequently made landfall at this strength near Casiguran, Philippines. Rapid weakening ensued due to interaction with the mountainous terrain of Luzon and the disheveled core of Koppu emerged over the West Philippine Sea on October 19.
context_section_description: A tropical disturbance formed in a monsoon trough late on October 10, over Enewetak Atoll. One day later, the Japan Meteorological Agency (JMA) upgraded the low-pressure area to a tropical depression, yet the low-level circulation center was exposed owing to strong vertical wind shear. On October 12, as the system kept consolidating with convection sheared to the west, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert; half a day after, the JMA started to issue tropical cyclone warnings about the tropical depression. The JTWC upgraded the system to a tropical depression early on October 13, although fragmented convective bands were wrapping tighter into a broad LLCC which remained exposed. At noon, tracking westward along the southern periphery of the deep-layered subtropical ridge, the system intensified into a tropical storm and was named Koppu by the JMA.
  Early on October 14, the storm entered the Philippine Area of Responsibility and received the name Lando from PAGASA, and deepened convection finally obscured the LLCC late on the same day, shortly before being upgraded to a severe tropical storm by the JMA. Under a favorable environment of low vertical wind shear and radial outflow, Koppu deepened rapidly and intensified into a typhoon in the afternoon of October 15, when a tightly-curved convective band was wrapping into an eye revealed by a microwave imagery. Intensification slowed down until an apparent but ragged eye formed one day later, as sea surface temperature was over 31 °C (88 °F) in the Philippine Sea. The 35 km (25 miles) eye became sharper on October 17, prompting the JTWC upgrading Koppu to a super typhoon with one-minute maximum sustained winds at 240 km/h (150 mph) in the afternoon, equivalent to Category 4 of the Saffir–Simpson hurricane wind scale. Around 01:00 PHT on October 18 (17:00 UTC on October 17), Koppu made landfall over Casiguran, Aurora in the Philippines; however, the JMA then reported that Koppu reached its peak intensity with ten-minute maximum sustained winds at 185 km/h (115 mph) and the central pressure at 920 hPa (27.17 inHg).
  Frictional effects from land interaction with Luzon started to erode the typhoon rapidly after landfall, despite excellent dual outflow channels. Before noon or in the afternoon on October 18, Koppu emerged into the South China Sea as a disorganized system which had begun to encounter with stronger easterly vertical wind shear. Tracking northward very slowly along the western periphery of an extension of the deep-layered subtropical ridge to the east-northeast, the proximity to Luzon was inhibiting the system from consolidating, leading the JMA to downgrade Koppu to a severe tropical storm when main convection had been sheared to the west early on October 19. Both the JTWC and then the JMA downgraded the highly unorganized system with a ragged LLCC to a tropical storm in the afternoon. Continuing hugging the coast of Luzon on October 20, Koppu drifted northeastward and then east-northeastward due to embedded within a weak complex steering environment with a near-equatorial ridge to the south and an induced ridge between Typhoon Champi and Koppu; convective organization was also hampered by being embedded in a mid-level trough along the western periphery of the subtropical ridge.
caption: Map plotting the track and the intensity of the storm, according to the Saffir–Simpson scale
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