Typhoon Isa

Last updated
Map key
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
Disc Plain black.svg Tropical cyclone
Solid black.svg Subtropical cyclone
ArrowUp.svg Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

In early April, the monsoon trough established itself across Micronesia near the equator. An area of convection within the trough developed in the Caroline Islands on April 9, and resembled the characteristics of a monsoon depression. Shortly thereafter, a large, yet weak low-level circulation formed within the system. The system drifted erratically for several days as it slowly organized; the system underwent several cycles of developing and losing convection. On April 11, the system maintained a persistent area of well-organized deep convection, and subsequent to an increase in upper-level outflow, the Joint Typhoon Warning Center (JTWC) classified the system as Tropical Depression 02W at 1800 UTC on April 11. Strong influence from the monsoonal westerlies left the depression drifting and slowly executing a loop to the northwest. Based on sufficient satellite classifications, JTWC upgraded the depression to Tropical Storm Isa early on April 12 while it was located 105 km (65 mi) of Pohnpei. [1] The Japan Meteorological Agency (JMA) simultaneously classified the system as a tropical depression and upgraded it to a tropical storm early on April 13. [2]

With the subtropical ridge to its north, [3] Isa tracked to the north and gradually curved to the west. It slowly intensified, due to it being a large tropical cyclone, and late on April 13 JTWC upgraded the storm to typhoon status; [1] at the same time, JMA continued to assess Isa as a minimal tropical storm, and did not upgrade it to a typhoon until April 16. [2] Isa maintained a nearly due-westward movement, although tropical cyclone prediction models anticipated a quick turn to the north. The JTWC recognized the northward model bias, which was described as under-analyzing the strength of the subtropical ridge. By April 16, the typhoon attained the equivalence of a Category 3 tropical cyclone on the Saffir-Simpson Hurricane Scale, and despite a potential threat to Guam the typhoon remained 260 km (160 mi) south of the island. It gradually curved to the north, and on April 20 JTWC classified Super Typhoon Isa as reaching peak 1-min winds of 270 km/h (170 mph). At this point, Isa became an annular typhoon, with a large eye and a lack of spiralform rainbands, while moving nearly due northward, through a weakness in the subtropical ridge. [1] Simultaneously, JMA assessed the typhoon as attaining peak 10-min winds of 155 km/h (95 mph). [2]

Shortly after peaking in intensity, Isa began to weaken, and by April 21 it dropped below "super typhoon" status. It accelerated to the northeast under the flow of the mid-latitudes, and the typhoon weakened more rapidly; [1] JMA downgraded Isa to a tropical storm on April 22, [2] which was followed suit by the JTWC the next day as upper-level wind shear increased. At 0600 UTC on April 23, the JTWC issued the last advisory on the system, [1] and the next day JMA classified Isa dissipated as it became absorbed by a cloud band from a large extratropical cyclone to the east of Japan. [1] [2]

Impact

Typhoon Isa visible from Guam NEXRAD Isa from Guam Radar.jpg
Typhoon Isa visible from Guam NEXRAD

Isa first affected Pohnpei as a tropical storm on April 12. While passing near the island, the storm produced moderate winds across the island, peaking at 95 km/h (60 mph). The winds downed several trees and tree limbs which destroyed 40% of the island's power lines. A few buildings reported roof damage. About 15% of the crops on Pohnpei were damaged, including losses to the banana and breadfruit crops. [4] After the passage of the typhoon, President of the Federated States of Micronesia Jacob Nena declared Pohnpei as a major disaster area due to the damage from Typhoon Isa and subsequent flooding; on April 20 heavy rainfall caused widespread mudslides and 19 fatalities on the island, though they were not related to Isa. [4] [5]

In Guam, the threat of Typhoon Isa postponed a flight from Guam to Honolulu, Hawaii for 48 hours. The flight was the last in Operation Pacific Haven  [ de ], which was a multimillion-dollar humanitarian effort to transport more than 6,600  Kurds in a political asylum to the mainland of the United States. [6] [7] The threat of the typhoon also canceled the first round of the Omega Tour golf event, which was the second professional golf tournament in the island's history. [8] [9] Though Typhoon Isa passed well to the south of Guam, one of its outer rainbands stalled across the island, which dropped heavy rainfall of 15–25 cm (6–10 in) across the island. The rainfall was welcome as it occurred during the dry season, [1] and largely contributed to rainfall at the Guam International Airport being 45% above normal from the period between January through April. [10] The rainband also produced wind gusts that reached 86 km/h (53 mph) at the island's Naval Air Station; the winds resulted in sporadic power outages across the island. The typhoon caused some light damage to buildings, particularly on the south side of the island. The combination of winds and sea salt caused damage to the island's tomato, okra, cucumber, and soybean crops. [4]

Typhoon Isa later dropped light rainfall on the island of Rota. [10] Across its path, damage from the storm totaled over $1 million (1997 USD, $1.9 million2024 USD). No deaths or injuries were reported. [4]

See also

Related Research Articles

<span class="mw-page-title-main">Typhoon Paka</span> Pacific typhoon in 1997

Typhoon Paka, known in the Philippines as Typhoon Rubing, was an extremely powerful and long-lived storm that devastated Guam and the Marshall Islands in December 1997. One of the strongest Pacific typhoons ever recorded in the month of December, Paka was the last tropical cyclone of the 1997 Pacific hurricane and typhoon seasons and the last of a record eleven super typhoons that formed in 1997. Paka, which is the Hawaiian name for Pat, developed on 28 November from a trough well to the southwest of Hawaii. The storm tracked generally westward for much of its duration, and on 7 December it crossed into the western Pacific Ocean. Much of its track was characterized by fluctuations in intensity, and on 10 December the cyclone attained typhoon status as it crossed the Marshall Islands. On 16 December, Paka struck Guam and Rota with winds of 230 km/h (140 mph), and it strengthened further to reach peak winds on 18 December over open waters as the final super typhoon of the year. Subsequently, it underwent a steady weakening trend, and on 23 December Paka dissipated.

<span class="mw-page-title-main">2004 Pacific typhoon season</span>

The 2004 Pacific typhoon season was an extremely active season that featured the second-highest ACE ever recorded in a single season, second only to 1997, which featured 29 named storms, nineteen typhoons, and six super typhoons. It was an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season ran throughout 2004, though most tropical cyclones typically develop between May and October. The season's first named storm and also the first typhoon, Sudal, developed on April 4, later was reached typhoon status two days later, and became the first super typhoon of the year three days later. The season's last named storm, Noru, dissipated on December 21.

<span class="mw-page-title-main">2003 Pacific typhoon season</span>

The 2003 Pacific typhoon season was a slightly below average yearlong period of tropical cyclogenesis exhibiting the development of 45 tropical depressions, of which 21 became named storms; of those, 14 became typhoons. Though every month with the exception of February and March featured tropical activity, most storms developed from May through October. During the season, tropical cyclones affected the Philippines, Japan, China, the Korean Peninsula, Indochina, and various islands in the western Pacific.

<span class="mw-page-title-main">2002 Pacific typhoon season</span>

The 2002 Pacific typhoon season was a slightly above average Pacific typhoon season, producing twenty-six named storms, fifteen becoming typhoons, and eight super typhoons. It had an ACE over 400 units, making it one of the most active seasons worldwide. It was an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season ran throughout 2002, though most tropical cyclones typically develop between May and October. The season's first named storm, Tapah, developed on January 11, while the season's last named storm, Pongsona, dissipated on December 11. The season's first typhoon, Mitag, reached typhoon status on March 1, and became the first super typhoon of the year four days later.

<span class="mw-page-title-main">2001 Pacific typhoon season</span>

The 2001 Pacific typhoon season was an average season with twenty-six named storms, sixteen typhoons and three super typhoons, with a near normal Accumulated Cyclone Energy (ACE) of 307.3 units. It ran year-round in 2001, with most tropical cyclones in the northwestern Pacific Ocean tending between May and November.

<span class="mw-page-title-main">1997 Pacific typhoon season</span> Typhoon season in the Western Pacific Ocean

The 1997 Pacific typhoon season was a record-breaking season featuring eleven tropical cyclones reaching super typhoon intensity, tying the record with 1965 with the most intense tropical cyclones globally, and was the ninth and last consecutive year of above-average tropical cyclone activity that started in 1989. Its extremely high activity produced highest ACE index ever index recorded in a single tropical cyclone season. In addition, this season had ten Saffir-Simpson Category 5-equivalent tropical cyclones, the most ever recorded, even greater than the 2005 Atlantic hurricane season, which had nearly half of the amount. The 1997–98 El Niño event was a contributing factor to this unusually high activity. Despite this, the season produced an average number of tropical storms, spawning 28 tropical storms.

<span class="mw-page-title-main">1992 Pacific typhoon season</span>

The 1992 Pacific typhoon season is the fourth consecutive above-average season, producing 31 tropical storms, 16 typhoons and five super typhoons. It had no official bounds; it ran year-round in 1992. Despite this, most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean.

<span class="mw-page-title-main">1988 Pacific typhoon season</span>

The 1988 Pacific typhoon season was a very active season in terms of named storms, though it only featured 11 typhoons and 1 super typhoon. It had no official bounds; it ran year-round in 1988, but most tropical cyclones formed between May and November. Tropical storms that formed in the entire west Pacific basin were assigned a name by the Joint Typhoon Warning Center. 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. This can often result in the same storm having two names.

<span class="mw-page-title-main">1987 Pacific typhoon season</span>

The 1987 Pacific typhoon season was a below average season, though it featured a relatively high amount of typhoons. It had no official bounds; it ran year-round in 1987, but most tropical cyclones formed between May and November. Tropical storms that formed in the entire basin were assigned a name by the Joint Typhoon Warning Center. 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. This can often result in the same storm having two names.

<span class="mw-page-title-main">Typhoon Pongsona</span> Pacific typhoon in 2002

Typhoon Pongsona was the last typhoon of the 2002 Pacific typhoon season, and was the second costliest United States disaster in 2002, only behind Hurricane Lili. The name "Pongsona" was contributed by North Korea for the Pacific tropical cyclone list and is the Korean name for the garden balsam. Pongsona developed out of an area of disturbed weather on December 2, and steadily intensified to reach typhoon status on December 5. On December 8 it passed through Guam and the Northern Mariana Islands while at peak intensity, with 10-minute sustained winds of 175 km/h (110 mph). It ultimately turned to the northeast, weakened, and became extratropical on December 11.

<span class="mw-page-title-main">Typhoon Neoguri (2008)</span> Pacific typhoon in 2008

Typhoon Neoguri, known in the Philippines as Typhoon Ambo, was the earliest tropical cyclone on record to strike China. The first named storm in the 2008 Pacific typhoon season, named after the Korean word for raccoon dog, it formed from a low pressure area on April 13 to the east of the Philippine island of Mindanao, and after crossing the island it intensified into a tropical storm in the South China Sea. Environmental conditions allowed for quick strengthening, with Neoguri attaining typhoon status on April 16. The typhoon reached its peak intensity on April 18 as it approached the island of Hainan, and subsequently it turned northward. Due to increased wind shear and cooler waters, Neoguri rapidly weakened and made landfall as a minimal tropical storm in southern China on April 19.

<span class="mw-page-title-main">Typhoon Keith</span> Pacific typhoon in 1997

Typhoon Keith was the tenth of a record eleven super typhoons to develop during the unusually intense 1997 Pacific typhoon season. Originating from a near-equatorial trough on October 26, the precursor depression to Keith slowly organized into a tropical storm. After two days of gradual strengthening, the storm underwent a period of rapid intensification on October 30 as winds increased to 195 km/h (121 mph). On November 1, the storm further intensified into a super typhoon and later attained peak winds of 285 km/h (177 mph). The following day, the powerful storm passed between Rota and Tinian in the Northern Mariana Islands. After fluctuating in strength over the following few days, a steady weakening trend established itself by November 5 as the typhoon accelerated towards the northeast. On October 8, Keith transitioned into an extratropical cyclone and was last noted early the following day near the International Dateline.

<span class="mw-page-title-main">Typhoon Kujira (2003)</span> Pacific typhoon in 2003

Typhoon Kujira, known in the Philippines as Typhoon Amang, was a long-lived tropical cyclone that lasted for 16 days and affected the island nations of Micronesia, Taiwan, and Japan in April 2003, as well as the earliest typhoon in a calendar year to ever make landfall on the latter. Forming from a broad area of disturbed weather as a tropical depression on April 9 well removed from any landmasses, Kujira quickly intensified in its early stages, and was upgraded to a tropical storm just two days after cyclogenesis. Strengthening slowed afterwards, though the storm attained typhoon intensity on April 14. Intensification continued and late on April 15, Kujira reached its peak intensity with winds of 165 km/h (103 mph) and a minimum barometric pressure of 930 mbar. Following peak intensity, Kujira began to track northwest and oscillate in strength, cresting an additional two times in intensity. On April 21, the typhoon was downgraded to tropical storm intensity and began to track erratically for several days east of Taiwan. However, on April 24, Kujira resumed a northward track and begin to weaken, and on April 24 was downgraded to tropical depression strength as it made landfall on Kyushu. Following landfall Kujira transitioned into an extratropical cyclone and continued to persist before these extratropical remnants crossed the International Dateline towards the end of April 2003.

<span class="mw-page-title-main">Typhoon Yuri</span> Pacific typhoon in 1991

Typhoon Yuri was the most intense tropical cyclone in 1991 in terms of minimum central pressure. The nineteenth typhoon and final super typhoon of the 1991 Pacific typhoon season, Yuri was a tropical disturbance that strengthened into a tropical depression on November 22 in the Philippine Sea. Moving rather slowly at first, the system continued to intensify, and was given the name Yuri. It had become a severe tropical storm about 1,480 kilometers east of Truk Island and took on a west-northwestward track at 22 km/h. Typhoon intensity was attained that night when Yuri was 1,050 km. Yuri turned more to the west on 26 November and reached peak intensity the following morning packing winds of over 220 km/h near its centre. Moving northwestwards at 30 km/h, Yuri passed 140 km to the south-southwest of Guam on the evening of November 27. After recurving November 29, Yuri accelerated northeastwards on November 30 and weakened to a severe tropical storm that night. By the morning of December 1, it had degenerated into a tropical storm about a few hundred kilometers east-northeast of Iwo Jima. Extratropical transition was completed soon afterward, and the storm's remnants persisted until December 3.

<span class="mw-page-title-main">Typhoon Mitag (2002)</span> Pacific typhoon in 2002

Typhoon Mitag, known in the Philippines as Typhoon Basyang, was the first super typhoon on record in the month of March. The second storm of the 2002 Pacific typhoon season, Mitag developed from a trough near the equator on February 25 near the Federated States of Micronesia (FSM). It moved westward through the archipelago and intensified into a typhoon before passing near Yap on March 2. High winds and heavy rainfall affected the state, resulting in an islandwide power outage and destroying hundreds of houses. Mitag caused severe crop damage that resulted in food shortages. The rainfall and storm surge flooded much of the coastline as well as Yap's capital, Colonia. Damage totaled $150 million, mostly from crop damage. There was one death related to the storm's aftermath.

<span class="mw-page-title-main">Typhoon Lupit (2003)</span> Pacific typhoon in 2003

Typhoon Lupit, known in the Philippines as Typhoon Yoyoy, destroyed the food supply in several small islands in Yap State in the Federated States of Micronesia (FSM). It formed on November 18, 2003, from the monsoon trough to the west of the Marshall Islands. Early in its duration, it moved generally to the west or west-southwest. On November 21, the depression intensified into Tropical Storm Lupit, the 21st storm named by the Japan Meteorological Agency of the 2003 Pacific typhoon season. Two days later, it strengthened into a typhoon and developed an eye. Lupit later began a prolonged movement to the northwest, during which it passed near several islands in Yap State. The typhoon reached peak intensity on November 26, with peak 10-minute sustained winds of 185 km/h (115 mph). It later weakened due to increasing wind shear and drier air, and after recurving to the northeast, Lupit became extratropical south of Japan on December 2.

<span class="mw-page-title-main">Typhoon Dolphin (2015)</span> Pacific typhoon in 2015

Typhoon Dolphin was a powerful tropical cyclone that produced the first typhoon-force winds on Guam since Typhoon Pongsona in 2002. The seventh named storm of the 2015 Pacific typhoon season, Dolphin formed on May 6 in the vicinity of the Federated States of Micronesia (FSM). Moving eastward at first, the storm slowly organized before beginning a north and west-northwest trajectory. Dolphin intensified into a typhoon before passing between Guam and Rota on May 15, producing typhoon-force winds on both islands. It later rapidly intensified as it curved to the north. The American-based Joint Typhoon Warning Center (JTWC) designated Dolphin as a super typhoon, while the Japan Meteorological Agency (JMA) estimated 10 minute sustained winds of 185 km/h (115 mph). Dolphin turned to the northeast and weakened, becoming extratropical on May 20 and exiting the western Pacific basin on May 24.

<span class="mw-page-title-main">Typhoon Songda (2004)</span> Pacific typhoon in 2004

Typhoon Songda, known in the Philippines as Typhoon Nina, was the sixth-costliest typhoon on record. The 18th named storm of the 2004 Pacific typhoon season, Songda developed on August 26 near the Marshall Islands. Following a path that Typhoon Chaba took nine days prior, Songda moved west-northwestward and strengthened quickly amid favorable conditions.

<span class="mw-page-title-main">Typhoon Wutip (2019)</span> Pacific typhoon in 2019

Typhoon Wutip, known in the Philippines as Tropical Depression Betty, was the most powerful February typhoon on record, surpassing Typhoon Higos of 2015. The third tropical cyclone, second tropical storm, and the first typhoon of the 2019 Pacific typhoon season, Wutip originated from a low-pressure area on February 16, 2019, that generally tracked westward, passing just south of the Federated States of Micronesia (FSM), before organizing into a tropical depression on February 18. The depression was later classified a tropical storm a day later, attaining the name Wutip from the Japan Meteorological Agency. The storm gradually intensified as it turned northwest, before it underwent rapid intensification on February 23, while passing to the southwest of Guam, and reached its first peak intensity. With winds of 270 km/h (165 mph) estimated by the Joint Typhoon Warning Center, Wutip became the first Category 5-equivalent super typhoon on record in the month of February. Wutip underwent an eyewall replacement cycle shortly afterward and weakened. The storm finished its cycle on February 24, rapidly intensifying once again. Wutip reached a secondary peak intensity the following day, again attaining Category 5-equivalent winds. Thereafter, Wutip rapidly weakened for the rest of its lifespan from strong vertical wind shear, before dissipating over the Philippine Sea on March 2.

<span class="mw-page-title-main">Typhoon Faxai (2001)</span> Pacific typhoon in 2001

Typhoon Faxai was the strongest tropical cyclone worldwide in 2001. The twenty-fifth named storm and the sixteenth typhoon of the 2001 Pacific typhoon season, Faxai originated from a circulation in the monsoon trough. The system remained stationary for several days near Kosrae, pouring heavy rain that knocked down power. An indirect death occurred on the island as well. As the storm steadily intensified, Faxai moved west-northwestward at a very slow pace as it neared Pingelap, damaging crops, before bringing strong winds and rainfall that produced two landslides in Pohnpei on December 20. Intensity fluctuated, but convection in the core became more defined and by December 21, Faxai had intensified into a typhoon. A period of rapid intensification then followed, and by early December 23, Faxai reached its peak intensity.

References

  1. 1 2 3 4 5 6 7 Joint Typhoon Warning Center (1999). "Super Typhoon Isa (02W) ATCR". Archived from the original on 2011-06-07. Retrieved 2007-04-25.
  2. 1 2 3 4 5 Japan Meteorological Agency (1997). "1997 Western Pacific Best Track". Archived from the original on 2007-09-29. Retrieved 2007-04-15.
  3. Joint Typhoon Warning Center (1999). "Tropical Storm Jimmy (03W) ATCR". Archived from the original on 2011-06-07. Retrieved 2007-04-20.
  4. 1 2 3 4 National Climatic Data Center (1997). "Event Report for Guam". Archived from the original on 2008-05-22. Retrieved 2007-04-26.
  5. Federated States of Micronesia Information Service (1997-04-25). "Nena Declared Pohnpei Disaster, Asked President Clinton Likewise" . Retrieved 2007-04-26.
  6. Staff Writer (1997-04-16). "Storm delays last flight of 300 Kurds from Guam". Honolulu Star-Bulletin. Archived from the original on 2007-02-11. Retrieved 2007-04-26.
  7. Office of the Assistant Secretary of Defense (Public Affairs) (1997-04-15). "Operation Pacific Haven Wraps Up Humanitarian Efforts". U.S. Department of Defense. Retrieved 2007-04-26.
  8. Agence France Presse (1997-04-16). "Typhoon Isa looks likely to bring havoc to the start".
  9. Agence France Presse (1997-04-18). "China's Wu Xiangbing and Taiwan's Tsai Chi-huang over".
  10. 1 2 Alan C. Hilton (1998). "Pacific ENSO Update - 2nd Quarter 1997 - Vol. 3 No. 2". National Oceanic and Atmospheric Administration.
Typhoon Isa
Isa 1997-04-20 0500Z.png
Typhoon Isa at peak intensity on April 20