2003 Pacific typhoon season

Season overview

Measured by the number of storms, 2003 was a modest year for the western Pacific, but an unusually large share of those storms became intense. The archive's 22 tropical storms fall short of the long-term average of about 26 used by the Tropical Storm Risk consortium, yet its 17 typhoons sit slightly above that group's average of about 16. Eleven storms reached major typhoon strength of 96 kt or more, and the season's accumulated cyclone energy came to 333.4.

Sea surface temperatures across the western equatorial Pacific, including the South China Sea, ran above normal for much of the year. Thunderstorm activity persisted at low latitudes around the Philippines, and storms tended to form farther southwest than the 1971 to 2000 average. Pre-season forecasts, built largely on a neutral outlook for the El Niño–Southern Oscillation, had called for a near-average year.

How the season unfolded

Typhoon Kujira opened the archive's season in early April and lasted more than two weeks, becoming the first typhoon of the year on April 12 and peaking at 135 kt on April 16. It killed two people on Pohnpei soon after forming, then swung past the Philippines and Taiwan before weakening and crossing Kyushu. Late May brought a cluster of storms: Typhoon Chan-Hom near Chuuk, Tropical Storm Linfa off western Luzon and Tropical Storm Nangka in the South China Sea. Typhoon Soudelor followed in June, passing over Iriomote-jima on its way to Japan and South Korea.

After a quiet start to July, the pace picked up in mid-month when Typhoon Koni and Typhoon Imbudo formed almost together. Late July through early September was the busiest phase of the year: Typhoon Morakot crossed Taiwan into Fujian, Typhoon Etau hit Okinawa and mainland Japan, Typhoon Krovanh raked Luzon, Hainan and northern Vietnam, Tropical Storm Vamco brushed Taiwan, and Typhoon Dujuan came ashore near Hong Kong.

September belonged to Typhoon Maemi, followed by Typhoon Choi-Wan and Typhoon Koppu, which both curved away over Japan's outlying islands. In October, Typhoon Ketsana and Typhoon Parma grew side by side from the same monsoon trough and stayed over open water, while Typhoon Melor crossed northeastern Luzon at the start of November. Typhoon Nepartak and Typhoon Lupit carried activity through November, and a final unnamed tropical storm, called Zigzag by the Philippine weather service, came ashore in northeastern Mindanao before dissipating on December 27.

Strongest storms

Typhoon Maemi was the season's most intense storm, reaching one-minute winds of 150 kt and a central pressure of 885 hPa on September 10 as it approached the southern Ryukyu Islands. Typhoon Lupit came close in late November, peaking at 145 kt and 892 hPa in the Philippine Sea after it had crossed Micronesia; it was also the longest-lived storm of the year, spending about 19 days in the record.

Below those two Category 5 storms sat a deep field of Category 4 typhoons. Kujira reached 135 kt in April, Imbudo and Parma each peaked at 130 kt, and Dujuan and Ketsana reached 125 kt. Parma's strength was especially unusual for where it occurred: it peaked near 30 degrees north on October 24, then made a slow week-long loop before a second burst of strengthening on October 29.

Notable landfalls and impacts

Typhoon Maemi was the most destructive storm of the year. After its eyewall crossed Miyako-jima, where one person was killed by flying glass, it made landfall just west of Busan on September 12. Jeju Island set national records for wind gust and low pressure. In South Korea, Maemi killed 117 people and caused ₩5.52 trillion in damage, about US$4.8 billion in 2003 currency; port damage in Busan disrupted exports for months, and the rice harvest was the poorest in 23 years.

Typhoon Imbudo struck northern Luzon on July 22, the strongest typhoon to hit the Philippines in five years, and damaged or destroyed 62,314 houses there. The Philippines reported 64 deaths and P4.7 billion in damage, about US$86 million in 2003 currency. Imbudo then made a second landfall near Yangjiang in Guangdong on July 24, where eight people died; 12 more died in Guangxi, and losses in China reached about ¥4.45 billion, or US$297 million in 2003 currency.

Typhoon Dujuan passed just south of Taiwan near peak strength and made landfall east of Hong Kong on September 2 as the strongest typhoon to strike the Pearl River Delta since 1979. A half-finished building collapsed in Shenzhen, killing 16 construction workers, and the storm killed 40 people across Guangdong, with damage in China of about ¥2.3 billion, or US$277 million in 2003 currency.

Japan took repeated blows. Typhoon Etau crossed Okinawa and made landfall on Shikoku on August 8, then moved over Honshu and Hokkaido, killing 20 people nationwide and causing ¥35.1 billion in damage, about US$294.8 million in 2003 currency. In the Philippines, the slow, erratic Tropical Storm Linfa dropped up to 723 millimeters of rain near Dagupan in late May and killed 41 people, while Typhoon Soudelor's rains led to 12 deaths in June.

Farther east, Typhoon Lupit damaged or destroyed about 200 homes in Chuuk State and wrecked crops and water supplies on Ulithi and Fais in Yap State, with damage of about US$1.7 million in 2003 currency across the Federated States of Micronesia and no deaths. In the South China Sea, Typhoon Krovanh and Typhoon Nepartak both hit Hainan; Nepartak's rain helped break a severe drought on the island but left about US$197 million in 2003 currency in crop and property damage.

Agency counts and retired names

Counts for 2003 differ by agency because each measures wind differently. The Japan Meteorological Agency, which names storms for the region using ten-minute average winds, recognized 21 tropical storms and 14 typhoons. The Joint Typhoon Warning Center, using one-minute winds, counted 23 tropical storms and 17 typhoons. That total includes Tropical Storm Yanyan, a weak January system that is not among the tracks mapped here, which is why the archive's count stands at 22. Because a one-minute average yields higher wind values than a ten-minute average, the archive lists Koni, Morakot and Melor as typhoons while the Japan Meteorological Agency kept them below typhoon strength, and it counts two unnamed October and December storms as tropical storms that the Japan Meteorological Agency never named.

Pressure estimates differ for the same reason. The archive's 885 hPa for Maemi comes from the Joint Typhoon Warning Center, which converts estimated winds to pressure, while the Japan Meteorological Agency estimated 910 hPa. Observers on Miyako-jima measured 912 hPa as the eyewall passed, among the lowest pressures recorded in Japan.

After the season, the names Imbudo and Maemi were retired and replaced by Molave and Mujigae. Yanyan was removed at Hong Kong's request and replaced by Dolphin, and the spelling of Koni was corrected to Goni. The Philippine weather service also retired Harurot, its local name for Imbudo, replacing it with Hanna.