The 1989 Pacific typhoon season was the second consecutive to have above average tropical cyclone activity. It was an extremely active season reaching 32 tropical storms, 20 typhoons and five super typhoons. It has no official bounds; it ran year-round in 1989, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November.Gary Padgett. May 2003 Tropical Cyclone Summary. Retrieved 2006-08-26. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean. The first storm, Winona, formed on January 15, while the final storm, Jack, dissipated on December 27. This season was also quite a deadly season that were caused by a few notable storms such as Tropical Storm Cecil, which was the worst storm to impact Vietnam in over 50 years, and Typhoon Gay, which directly impacted the Malay Peninsula as the worst typhoon in 35 years. Both of these storms make up around half of the total fatalities of the entire season alone.
The scope of this article is limited to the Pacific Ocean, north of the equator and between 100°E and 180th meridian. Tropical Storms formed in the entire west pacific basin were assigned a name by the Joint Typhoon Warning Center. Tropical depressions in this basin have the "W" suffix added to their number. Tropical depressions that enter or form in the Philippine area of responsibility are assigned a name by the Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA.
Season summary
Throughout 1989, several large-scale factors across the western Pacific Ocean displaced unusual characteristics that presented unique difficulties to forecasters. In their annual tropical cyclone report for 1989, the Joint Typhoon Warning Center regarded the season as one of the most challenging and unique years in their history. During much of the year, a very broad monsoon trough was present and resulted in significant diurnal fluctuations in convective activity that inhibited rapid development of many disturbances. The mid-tropospheric ridge was unusually narrow and led to difficulties in forecasting straight-running storms. Additionally, the tropical upper tropospheric trough (TUTT) had a major role in the development of many systems, most notably Typhoon Gordon which formed from a single thunderstorm underneath a TUTT cell.
The season began with the unusual development of Tropical Storm Winona east of the International Date Line in early January. Remaining active for two weeks, the system crossed the basin before dissipating over the Philippines. Following a three-month lull in activity, a powerful typhoon developed in mid-April and was the second system in nine years to become a super typhoon during that month. By mid-May, an extensive monsoon trough had become established from the Bay of Bengal eastward into the South China Sea. Typhoon Brenda developed from this trough over the South China Sea and moved inland over southern China before dissipating. The typhoon left an area of enhanced low-level southerly flow in its wake that triggered the development of Typhoon Cecil at the end of the month. Two more storms developed during June – Typhoon Dot and Tropical Storm Ellis. The first was a strong typhoon that developed near the Caroline Islands and moved westward, eventually dissipating over Vietnam. The second was a poorly organized system that moved generally northward and struck Japan.
In early July, a surge in the monsoon trough over the basin resulted in the development of Tropical Storm Faye. While this system was over the Philippines, Typhoon Gordon developed underneath a TUTT cell to the east. Following Gordon's rapid intensification phase, a new tropical storm developed within an area of enhanced divergence associated with the same TUTT cell. Several days later, the monsoon trough became exceptionally active and spawned several consecutive cyclones in late-July: Irving over the South China Sea, Judy near the Mariana Islands, 12W near Taiwan, and Ken–Lola around the Ryukyu Islands. The development of seven tropical cyclones in July made it the most active July since 1973. The extreme activity continued into August with the formations of Mac, Nancy, Owen, Peggy, and 19W, all of which formed within the monsoon trough. The rapid succession of Nancy, Owen, and Peggy led to several days of binary interaction between the systems well to the south of Japan. Tropical Storm Roger developed near the Ryukyu Islands a few days after 19W dissipated and rapidly tracked northeastward through Japan. This was the only storm of the month not to develop within the monsoon trough. The final system of August, 21W, developed to the northeast of Guam and dissipated due to strong wind shear.
Heavy rains alongside several typhoons between June and September resulted in deadly flooding across parts of Anhui, Hebei, Hubei, Jiangsu, Jiangxi, Jilin, Sichuan, and Zhejiang provinces in China. The floods killed approximately 3,000 people and overall losses reached $2.7 billion.
Systems
Tropical Storm Winona
On January 15, Tropical Storm Winona crossed the International Date Line and entered the Western Pacific basin. Embedded within broad easterly flow, the storm turned west-southwestward, a heading it would retain until dissipation, and accelerated. This acceleration caused slight strengthening of the storm by enhancing winds on the north side of the low.
On January 16, Winona passed approximately south of Wake Island. Operationally, it was not until January 18 that the JTWC began issuing warnings on the system. At the same time, the JMA assessed Winona to have been a weak tropical storm with winds of . Around 0700 UTC on January 18, the ship MV Williams passed close to or through the center of Winona and measured a pressure of alongside sustained winds with gusts up to . This was the only direct measurement in relation to the cyclone. Early on January 19, the JTWC assessed Winona to have reached its peak intensity with winds as it passed just north of Saipan. Later that day, convection quickly diminished as Winona moved into a shallow air mass-produced by polar system to the north. The system maintained only intermittent convection for another day before making landfall in the central Philippines. The storm quickly weakened and dissipated on January 22 as it emerged into the South China Sea.
Before dissipating, the remnants of Winona tracked through the Philippines; however, no known impact resulted from its passage. Throughout its nearly two week existence, Winona traveled approximately across the Pacific Ocean.
Tropical Depression Atring
In late January, heavy rains affected much of Samar Island, resulting in widespread flooding. In some areas, flood waters reached depths of . At least 35 people died as a result of the floods and agricultural losses were estimated at $5 million. The flooding was soon worsened as several days of monsoonal rains followed in early February. By February 7, at least 61 people had been killed and many more were reported missing.
Typhoon Andy
Thunderstorm activity increased in coverage near Truk/Chuuk in the Caroline Islands on April 13. The system slowly developed, organizing into a tropical depression on April 18 while moving slowly to the west. On April 19, Andy began to move northward while continuing to intensify. The intense cyclone missed Guam by to the southeast, with winds peaking at on Guam. Thereafter, Andy recurved to the northeast and steadily weakened due to increased vertical wind shear out of the west, dissipating as a tropical cyclone on April 24. Andy became the second typhoon to form in April in nine years.Joint Typhoon Warning Center. 1989 Joint Typhoon Warning Center Tropical Cyclone Reports for the Northwest Pacific and North Indian Oceans. Retrieved on 2008-11-26.
Prior to Typhoon Andy's arrival, 14 B-52s and 3 KC-135s were relocated from Anderson Air Force Base in Guam to Hickam Air Force Base in Hawaii, while one KC-135 was sent to Clark Air Base in the Philippines. Nearly half of the schools in Guam were converted to public shelters. Approximately 1,100 people sought refuge across the island. On April 21, the typhoon's close passage brought sustained winds of and gusts up to to Guam. The storm's high winds downed many power lines, leaving about 15 percent of Guam without power for several hours. Overall damage from the storm was minimal despite the strong winds and no reports of major structural damage or injuries were received. Heavy rain also impact much of the southern Mariana Islands, amounting to about in Guam. These heavy rains caused pump malfunctions that left many residents without drinkable water.
Typhoon Brenda (Bining)
A tropical depression which formed in the monsoon trough on May 14 became a tropical storm on May 16 and struck Samar Island and southern Luzon in the Philippines that day. At least four ships sank and 50 people were killed in the Philippines. Brenda became a typhoon and reached a peak of winds before hitting southern China on May 20. The storm brought torrential flooding, resulting in at least 84 casualties and widespread damage in China. In Hong Kong six people were killed and one was missing due to landslides and flooding.Joint Typhoon Warning Center. Typhoon Brenda. Retrieved on 2007-01-20.
On May 16, storm warnings were issued for 20 provinces across the Philippines as Brenda approached the country. Multiple commercial vessels were kept at port until the storm passed. Throughout the country, Brenda killed at least 18 people and left 6,000 more homeless. Additionally, 52 people were reported missing.
Severe Tropical Storm Cecil
Cecil originated as a tropical depression over the South China Sea on May 22. Tracking north-northwestward, the system steadily intensified, attaining peak winds of . The JTWC assessed Cecil to have been slightly stronger with one-minute sustained winds of . The storm made landfall near Hội An late on May 24 and quickly weakened. The lowest atmospheric pressure recorded on May 25, observed in Da Nang at an elevation of 6 meters above sea level, was 982.1 hPa. The system later dissipated over Laos on May 26. In Vietnam, heavy rains accompanying the storm, amounting to over in some areas, triggered catastrophic flooding that killed 751 people. Widespread structural and agricultural losses took place in addition to the significant loss of life, with damage estimated at ₫300 billion ($71.7 million). In the wake of the flooding, some international aid was sent to Vietnam, though most relief work was conducted by the government, local agencies, and the Red Cross.
Typhoon Dot (Kuring)
Originating from a tropical disturbance near Palau on June 4, Dot tracked west-northwestward towards the Philippines. Crossing the country on June 6, the system moved over the South China Sea and attained typhoon status. Late on June 8, Dot reached its peak intensity with winds estimated at . The system weakened slightly the next day before making landfall in Hainan Island. A weakened storm then entered the Gulf of Tonkin before striking northern Vietnam and dissipating on June 12.
Throughout its course, Typhoon Dot produced heavy rains in the Philippines, China and Vietnam, resulting in significant damage and eight fatalities. The most severe impacts took place on Hainan Island where 1,400 homes were destroyed and another 60,000 were damaged. In Vietnam, Dot killed six people and exacerbated flooding triggered in late May by Tropical Storm Cecil.
Severe Tropical Storm Ellis (Daling)