Typhoon Nock-ten, known in the Philippines as Super 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 afterwards before making eight landfalls over the Philippines. The typhoon weakened rapidly due to the landfalls as it entered the South China Sea on December 26, turned southwest, and ultimately dissipated on December 28 due to the winter monsoon.
Nock-ten was the third typhoon to have caused significant impacts in the Philippines, after typhoons Sarika and Haima only two months prior, both of which struck similar areas at a similar intensity. 13 people were known to have been killed by Nock-ten. Damage totals were estimated upwards of US$127.5 million, and because of this, the names Nock-ten and Nina were retired by the Japan Meteorological Agency and PAGASA name lists, respectively.
Meteorological history
On December 20, the Japan Meteorological Agency started to monitor a tropical depression that had formed about 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 °C. Although the eye became cloud-filled in the afternoon, it cleared again late on the same day and while the JMA did not raise its intensity estimate further, the JTWC did so.
On December 25, the JTWC reported that the Dvorak technique analyses at 03:00 UTC from "all reporting agencies" indicated a T-number of 7.0; therefore, the JTWC added a non-synoptic entry to the operational best track for that time, indicating one-minute maximum sustained winds of 260 km/h (160 mph), equivalent to Category 5 on the Saffir–Simpson scale. However, land interaction soon impacted the typhoon, as its convective cloud tops had become warmer. Later, Nock-ten made landfall over the Philippines eight times: Bato, Catanduanes at 18:30 PST (10:30 UTC) and Sagñay, Camarines Sur at 21:30 PST (13:30 UTC) on December 25; San Andres, Quezon at 02:00 PST (18:00 UTC), Torrijos, Marinduque at 04:30 PST (20:30 UTC), Verde Island, Batangas at 09:15 PST (01:15 UTC), Tingloy, Batangas at 10:10 PST (02:10 UTC), Calatagan, Batangas at 11:40 PST (03:40 UTC), and Lubang Island, Occidental Mindoro at 13:00 PST (05:00 UTC) on December 26.