2020 Pacific typhoon season

Season overview

By total energy 2020 was one of the quieter years in the western Pacific. The site's archive gives an accumulated cyclone energy (ACE) of 151.1, and the Joint Typhoon Warning Center's own tally of 155.7 was well below its 20-year mean of 274.2. The two figures differ slightly because the site counts only the tropical stage of each track in the international best-track archive, while JTWC works from its own post-season best tracks. JTWC numbered 26 tropical cyclones, fewer than its long-term mean of 30.

The year began with neutral El Niño–Southern Oscillation conditions, and a weak La Niña developed from August. Tropical Storm Risk, which had expected a slightly below-average season in May, cut its outlook through the summer, and by August it expected an ACE barely half of normal and one of the least active typhoon seasons on record. The year's activity was concentrated late: from May to July only two storms reached tropical-storm strength, while most of the season's energy came between late August and mid-November.

How the season unfolded

No tropical cyclone formed in the first four months of the year, one of the latest starts on record and the latest since 2016. The first, Typhoon Vongfong, became a tropical storm east of the Philippines on 11 May, reached typhoon strength on 13 May and struck Eastern Samar the next day before crossing the Visayas into Luzon. A month later Tropical Storm Nuri formed near Samar, crossed Luzon as a depression and strengthened briefly over the South China Sea before coming ashore in southern China.

Then the basin went quiet again. Only a weak depression, named Carina by the Philippine weather service, formed in July, and for the first time since reliable records began no tropical storm developed in the western Pacific during that month. Activity finally resumed at the start of August with Tropical Storm Sinlaku, whose precursor crossed Luzon before it struck northern Vietnam, and Typhoon Hagupit, which came ashore near Wenzhou in eastern China on 3 August.

August became the season's first busy stretch, with nine storms reaching tropical-storm strength. Tropical Storm Jangmi crossed the Ryukyu Islands into South Korea, Typhoon Mekkhala struck Fujian, and Tropical Storm Higos hit the Pearl River Delta. The month ended with three strong typhoons in quick succession: Typhoon Bavi, Typhoon Maysak and Typhoon Haishen, all of which tracked north toward Korea and Japan between late August and early September.

The rest of September was comparatively calm, with Tropical Storm Noul striking central Vietnam, Tropical Storm Dolphin forming south of Japan and Typhoon Kujira briefly reaching typhoon strength far out at sea. October was the busiest month of the year. Typhoon Chan-Hom, the longest-lived system of the season in the archive, drifted south of Japan for more than two weeks, while Tropical Storm Linfa, Tropical Storm Nangka and a depression called Ofel by the Philippine weather service followed one another into Vietnam. Typhoon Saudel crossed northern Luzon, and the month closed with Typhoon Molave, Typhoon Goni and Tropical Storm Atsani active together.

The late-season run continued into November with Tropical Storm Etau, which crossed the central Philippines into Vietnam, and Typhoon Vamco, the last typhoon of the year. The final system, Krovanh, crossed Mindanao and Palawan in December; the Japan Meteorological Agency named it a tropical storm, but in the US-agency winds used by the site it peaked at 30 knots, and its last tropical-stage observation on 24 December ended the season in the archive.

Strongest storms

Typhoon Goni was the strongest storm of the season and, according to JTWC, the most intense western Pacific cyclone since Typhoon Haiyan in 2013. It formed west of the Mariana Islands in late October, and a passing trough to its north weakened the steering ridge and opened a strong poleward outflow channel, allowing several rounds of rapid intensification. An eyewall replacement over roughly 20 hours on 30 and 31 October barely slowed it, and Goni reached its peak of 170 knots with a pressure of 884 hPa at 18:00 UTC on 31 October, just before landfall on Catanduanes.

JTWC contrasted Goni with Typhoon Molave, which had formed in a similar area only days earlier but moved west under an unbroken subtropical ridge and strengthened only steadily before reaching the Philippines. Molave reached its peak of 105 knots later, over the South China Sea, before striking central Vietnam. Goni, by contrast, weakened rapidly over the Philippine terrain, found a rebuilt ridge and waters cooled by Molave when it reached the South China Sea, and came ashore in Vietnam only as a weak depression.

Typhoon Haishen was the second strongest, peaking at 135 knots on 4 September with a pressure of 913 hPa, and was the season's first super typhoon on JTWC's scale. Typhoon Maysak peaked at 120 knots on 1 September, and Typhoon Vamco reached 115 knots over the South China Sea on 13 November after crossing Luzon. The remaining major typhoons were Molave, Typhoon Bavi and Typhoon Vongfong, each peaking at 100 to 105 knots.

Notable landfalls and impacts

The Philippines bore the brunt of the late season. Goni made its first landfalls at peak intensity on Catanduanes and in Albay, prompting the Philippine weather service's highest wind signal for only the second time, after Typhoon Haima in 2016. The national disaster agency reported at least 25 deaths and 17.9 billion pesos (US$369 million in 2020 dollars) of infrastructure and agricultural damage, with a wider estimate of US$1.04 billion in the country. Molave had crossed the Bicol Region days earlier, leaving 27 deaths and 4.22 billion pesos (US$87.2 million) of damage in the Philippines by the agency's count.

Two weeks after Goni, Typhoon Vamco made three landfalls in Quezon Province and crossed Luzon, with the Cagayan Valley recording the highest damage. The national disaster agency reported 101 validated deaths and 10 people missing, and more than five million people were affected; the insurance broker Aon estimated total economic losses at over US$1 billion in 2020 dollars. Earlier in the year, Vongfong's May landfall on Eastern Samar was the first of seven as it tracked across the central islands into Luzon.

Central Vietnam suffered a prolonged run of storms from mid-September through November. Noul killed 6 people and caused about US$30.4 million of damage in Vietnam. Linfa, although only a tropical storm, brought exceptional rainfall to central Vietnam, and together with the flooding that followed it left 104 people dead and 38 missing in Vietnam and Cambodia. Nangka, Ofel, Molave, Goni, Etau and Vamco then struck or brushed the same region, adding to damage in areas still recovering from earlier storms.

Farther north, Bavi, Maysak and Haishen reached the Korean Peninsula within about two weeks. Bavi made landfall in North Pyongan Province in North Korea on 27 August, Maysak came ashore near Busan early on 3 September local time and crossed into North Korea and northeast China, and Haishen passed close to Japan's southwestern islands, prompting large evacuations in western Japan, before landfall near Ulsan on 7 September. In China, Mekkhala caused about 1.1 billion yuan (US$159 million in 2020 dollars) of damage in Zhangzhou, while Higos prompted a No. 10 signal in Macau and the evacuation of more than 65,000 people.

Names, retirements and counting

Five international names were retired after the season because of the deaths and damage their storms caused: Vongfong, Linfa, Molave, Goni and Vamco, later replaced by Penha, Peilou, Narra, Gaenari and Bang-Lang. The Philippine weather service also retired the local names Ambo, Quinta, Rolly and Ulysses, which it had given to Vongfong, Molave, Goni and Vamco. The season also saw the first use of the name Saudel, which replaced Soudelor after 2015.

Agency counts for 2020 differ because they measure winds differently. The Japan Meteorological Agency, which uses ten-minute winds, named 23 tropical storms and classed 10 as typhoons; Mekkhala and Kujira reached typhoon strength only in the one-minute winds used by JTWC and the site, which is why the site counts 12 typhoons, matching JTWC. The site's 23 tropical storms include JTWC's unnamed Tropical Storm 06W south of Japan in August, which the Japanese agency kept as a depression, but not Krovanh, which reached tropical-storm strength only in ten-minute winds. The Philippine weather service counted 22 systems in its own area of responsibility.