The 1981 Pacific typhoon season was a slightly above average season that produced 29 tropical storms, 13 typhoons and two intense typhoons. The season ran throughout 1981, though most tropical cyclones typically develop between May and November.Gary Padgett. May 2003 Tropical Cyclone Summary. Retrieved 2007-01-05. The season's first named storm, Freda, developed on March 12 while the final storm, Lee, dissipated on December 29. Tropical cyclones only accounted for 12 percent of the rainfall in Hong Kong this season, the lowest percentage for the protectorate since 1972.Hong Kong Royal Observatory (1982). Meteorological Results 1981: Part III - Tropical Cyclone Summaries. Retrieved of 2008-11-10.
The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and 180th meridian. Within the northwestern Pacific Ocean, there are two separate agencies that assign names to tropical cyclones which can often result in a cyclone having two names. The Joint Typhoon Warning Center (JTWC) will name a tropical cyclone should it be judged to have 1-minute sustained wind speeds of at least 65 km/h (40 mph) anywhere in the basin, whilst the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigns names to tropical cyclones which move into or form as a tropical depression in their area of responsibility located between 135°E and 115°E and between 5°N–25°N regardless of whether or not a tropical cyclone has already been given a name by the JTWC. The Japan Meteorological Agency (JMA) also monitors the whole basin and uses the 10-minute sustained wind scale. Moreover, the JTWC also assigns a number with a "W" suffix when a system has strengthened into a tropical depression.
Season summary
The season started with Freda, which became the fourth March typhoon for the basin since 1959. The system passed west of Wake Island before dissipating on March 17. Gerald formed in mid-April near an upper-level low, and recurved just east of Guam bringing the island heavy rainfall. Holly formed in the middle of the tropical Pacific Ocean in late April, and dissipated far from land on May 7. Ike was the first system to form in the South China Sea, living during the second week of June before recurving across Taiwan and becoming an extratropical cyclone. June formed during the third week of June, and moved just east of Taiwan before approaching Japan as a nontropical cyclone. Kelly crossed the Philippines on July 1, moving into Vietnam on July 4. Lynn moved nearby the northern Philippines before making landfall in mainland China on July 7. Maury tracked near Taiwan, China, and eventually Vietnam as a remnant low during the third and fourth weeks of July. Nina formed on the northeast fringe of Maury, also moving into mainland China on July 23, three days after Maury. Ogden moved into Japan at the end of July, approaching Korea early in August.
Tropical Depression 11 formed in the tropical west Pacific, dissipating well east of Asia on August 2. Phyllis formed and remained southeast of Japan on August 3 and August 4. Roy meandered around the South China Sea between August 3 and August 9. Susan moved northwest through the open western Pacific during the second week of August. Thad moved north-northeast through its life cycle, moving through Japan on August 23. Vanessa moved northeast through the open western Pacific in mid-August. Warren moved west-northwest through Hainan Island and northern Vietnam during the third week of August. Agnes moved extremely close to eastern China before dissipating on September 1. Bill recurved southeast of Japan during the first week of September. Clara moved west-northwest near Luzon and into mainland China during the third week of September.
Doyle moved through the central Pacific during the third week of September. Elsie recurved south of Japan during the beginning of October. Fabian moved westward through the Philippines into Vietnam during the second week of October. Gay recurved near the Japanese coast on October 21 and 22. A tropical depression moved west-northwest into Vietnam on November 11. Hazen moved across the Central Philippines into mainland China by November 23. Irma moved across the northern Philippines and then south of Taiwan during late November. Jeff recurved east of mainland Asia during late November. Kit moved erratically westward towards the Philippines during mid-December. Lee moved across the central Philippines, dissipating across the South China Sea on December 28.
Systems Typhoon Freda
Freda was the first tropical cyclone in the western Pacific in 1981 and the fourth typhoon to occur in March since 1959. The incipient disturbance was nearly stationary near the Gilbert Islands for a few days, before drifting northwest and slowly intensifying. During the morning of the March 11 it was upgraded to a tropical depression. It tracked along the periphery of the subtropical ridge with slow development for the next few days. On March 14 intensification became more rapid and Freda became a typhoon. Passing west of Wake Island with maximum sustained winds of intensity, the island sustained wind gusts to typhoon force and waves to . As the typhoon moved more northeast, the cyclone weakened, and Freda was absorbed by March 17 into another extratropical cyclone.
Severe Tropical Storm Gerald
This cyclone initially formed in response to a mid to upper level cyclone southeast of Ponape on April 12. Thunderstorms developed near the upper level system, and an outflow pattern was present on satellite imagery, but a surface circulation did not materialize until April 15. The system became a tropical depression by that night. Steady intensification was seen until around midday on April 17 when a new upper level high formed to its east, inducing southerly vertical wind shear. Weakening began while the storm was located about east of Guam late on April 18. Moderate to heavy rainfall did occur on the island, with to being measured. After passing Guam, the remaining thunderstorm activity sheared away, leaving a low-level swirl which moved northwest. The cyclone was absorbed by a system approaching in the main belt in the Westerlies on April 19.
Tropical Storm Holly
A broad area of thunderstorm straddled the equator around the International Date Line beginning on April 21. A tropical system in the Southern Hemisphere was interacting with a strong system in the main belt of the Westerlies. Around this time, convective increased north of the equator, with a low level circulation forming near late on April 25. By midday on April 29 it had become a tropical depression as it continued to move westward. Holly became a tropical storm on April 30 and almost became a typhoon late on May 1. Southwesterly vertical wind shear began to weaken the cyclone thereafter, causing Holly to dissipate over the open Pacific Ocean.
Severe Tropical Storm Ike (Bining)
This cyclone formed in the South China Sea at the end of the monsoon transition season. Around noon on June 8 a broad area of lowered pressures was seen west of the Philippines. Moderate northeast wind shear displaced its mid-level center as far as from the surface center, which retarded development. By midday on June 9, Ike strengthened into a tropical storm. On its closest approach to Hong Kong, winds gusted to at Tate's Cairn.
An upper trough in the main belt of the Westerlies moved across Asia, which turned Ike to the northeast. Intensification continued as it accelerated, and Ike became a typhoon late on June 12. The cyclone reached its peak intensity as it made landfall on the island of Taiwan. Weakening substantially over the mountainous island, Ike attempted slight tropical redevelopment before it became an extratropical cyclone late on the morning of June 14. Eight perished due to Ike, four from Taiwan and four from the Philippines.
Typhoon June (Kuring)
A tropical upper tropospheric trough (TUTT) was located over the Philippine Sea early in June. In response, a tropical disturbance formed in Palau. An upper cyclone to the disturbance's northeast led to development of the disturbance. As the TUTT cell moved to the disturbance's northwest, intensification sped up and a low level circulation center formed on June 15 about north of Palau. By the afternoon of June 17, the cyclone had become a tropical storm. June tracked northwest towards Taiwan, and by late on June 19, had reached its maximum intensity as a typhoon. About southeast of Taipei, June recurved to the north, and gradually weakened. While approaching Japan, the cyclone linked up with a frontal boundary and became an extratropical cyclone late on June 22.
Severe Tropical Storm Kelly (Daling)
A tropical disturbance organized into a tropical depression east of the Philippines on June 28. It tracked westward, reaching tropical storm on June 30 before hitting the central Philippines. Kelly weakened over the islands, but restrengthened in the South China Sea, attaining typhoon status on July 2. The typhoon hit southern Hainan Island on July 3, bringing wind gusts to at Tate's Cairn in Hong Kong. The cyclone then crossed the Gulf of Tonkin as a weakening tropical storm, and made landfall on northern Vietnam on July 4 as a tropical storm with maximum sustained winds of . The lowest atmospheric pressure recorded on July 5 (UTC+7), observed in Vinh at an elevation of 6 meters above sea level, was . Kelly dissipated the next day, after causing torrential flooding and mudslides, resulting in 200 casualties and leaving thousands homeless.
Severe Tropical Storm Lynn (Elang)
On the morning of June 27, an area of enhanced thunderstorm activity was spotted just south of Ponape along a weak portion of the monsoon trough. As Tropical Storm Kelly led to some vertical wind shear over the system, the disturbance was slow to organize. A low-pressure area formed late on June 29. By late on July 2, Kelly's negative influence on the disturbance abated, allowing for further development. Early on July 3, the system developed into a tropical depression, and by afternoon Lynn was a tropical storm. Previously moving at a fast pace to the west, the cyclone slowed as it passed by the northern fringe of the Philippines. Inflow from the South China Sea led to convection focusing in the terrain of the Philippines, which distorted Lynn's convective pattern. Lynn was the second tropical cyclone is three days to impact the Philippines. The cyclone took 30 hours to track across the northern portion of the archipelago.
It took until late on July 4 for the storm to recover from its Philippine interaction and redevelop a central dense overcast and quicken its pace to the west across Luzon. Turning northwest across the South China Sea, light to moderate easterly wind shear prevented Lynn's development into a typhoon. The cyclone struck Chuan-Tao, China early on July 7. Very heavy rainfall led to mudslides which took 22 lives and left tens of thousands homeless. In Hong Kong, winds gusted to at Tai O, and a total of of rainfall was recorded at Cheung Chau. Severe Tropical Storm Lynn had the Hong Kong observatory put the Typhoon 8 signal up for 28 Hours and 45 minutes.
Severe Tropical Storm Maury (Huling)