Typhoon Nock-ten (2016)

Typhoon Nock-ten (Nina)

Typhoon (JMA scale)
Category 5 (Saffir–Simpson scale)
Typhoon Nock-ten approaching the Philippines at peak intensity on December 25
Formed	December 20, 2016
Dissipated	December 28, 2016
Highest winds	10-minute sustained: 195 km/h (120 mph) 1-minute sustained: 260 km/h (160 mph)
Lowest pressure	915 hPa (mbar); 27.02 inHg
Fatalities	8 confirmed, 16 missing
Damage	$104.1 million (2016 USD)
Areas affected	Caroline Islands, Philippines, Vietnam
Part of the 2016 Pacific typhoon season

Typhoon Nock-ten, known in the Philippines as Typhoon Nina, was the strongest Christmas Day tropical cyclone worldwide in terms of 1-minute sustained winds. Forming as a tropical depression southeast of Yap and strengthening into the twenty-sixth tropical storm of the annual typhoon season on December 21, 2016, Nock-ten intensified into the thirteenth typhoon of the season on December 23. Soon afterwards, the system underwent explosive intensification and became a Category 5-equivalent super typhoon early on December 25. Nock-ten weakened shortly before making eight landfalls over the Philippines.

During December 20, the Japan Meteorological Agency started to monitor a tropical depression that had developed, about 1,090 km (675 mi) to the southeast of Yap Island in the Federated States of Micronesia. The broad and poorly organized system was being affected by moderate to high vertical wind shear, which was being offset by warm sea surface temperatures. Soon, the JTWC upgraded the system to a tropical depression, with the designation of 30W, based on improved environmental conditions and an ASCAT image. Late on the same day, when central convection was increasing and consolidating over a defined low-level circulation center (LLCC), both the JMA and the JTWC upgraded it to a tropical storm, with the former assigning the name Nock-ten. One day later, late on December 22, the JMA upgraded the system to a severe tropical storm, and Nock-ten started to form an eye revealed by microwave imagery.

Tracking west-northwestward and then westward along the southern periphery of a deep-layered subtropical ridge, Nock-ten intensified into a typhoon at noon UTC on December 23. Immediately after that, explosive intensification commenced with a sharp eye embedded in a symmetric central dense overcast feature. At 06:00 UTC on December 24, Nock-ten reached its peak intensity with estimated ten-minute maximum sustained winds of 195 km/h (120 mph) and the central pressure at 915 hPa (27.02 inHg); therefore, it was the latest-forming typhoon of such intensity or stronger on record. The JTWC also upgraded Nock-ten to a Category 4-equivalent super typhoon, when the system was in an area of low vertical wind shear, excellent dual-channel outflow, and sea surface temperatures of 29 ºC. Although the eye became cloud-filled in the afternoon, it cleared again again late on the same day and while the JMA did not raise its intensity estimate further, the JTWC did so.