Meteorological history | |
---|---|
Formed | May 29, 2021 |
Extratropical | June 5, 2021 |
Dissipated | June 6, 2021 |
Tropical storm | |
10-minute sustained (JMA) | |
Highest winds | 75 km/h (45 mph) |
Lowest pressure | 998 hPa (mbar); 29.47 inHg |
Tropical storm | |
1-minute sustained (SSHWS/JTWC) | |
Highest winds | 85 km/h (50 mph) |
Lowest pressure | 996 hPa (mbar); 29.41 inHg |
Overall effects | |
Fatalities | 11 |
Missing | 2 |
Damage | $6.39 million (2021 USD) |
Areas affected | Palau, Philippines, Taiwan, Japan |
IBTrACS | |
Part of the 2021 Pacific typhoon season |
Tropical Storm Choi-wan, known in the Philippines as Tropical Storm Dante, was a tropical storm which caused moderate flooding and damage in the Philippines and also affected Taiwan. The third named storm of the 2021 Pacific typhoon season, Choi-wan originated from an area of low pressure, located south-southeast of Guam near a brewing system. Fueled by an environment favorable for tropical cyclogenesis, it developed into a tropical depression, two days later as it moved westward. At 00:00 UTC on May 31, the system strengthened to a tropical storm and was named Choi-wan by the JMA. Although the storm was still located in the conductive conditions off the Philippine Sea while moving northwestward, a tropical upper tropospheric trough to the northeast halted the system's intensification, with Choi-wan's convection displaced to the south of its circulation on satellite imagery.
Heavy rains caused floods across a majority of Mindanao and Visayas; 11 fatalities were reported and 2 people are missing.[1] In the southwestern Philippines, 45,000 people were impacted while more than 12,000 sheltered at evacuation centers to ride out the cyclone.[2] In Western Visayas, 895 people were also evacuated on June 2.[3] Around 4,813 individuals were displaced in Agusan del Norte.[4]
On May 27, the Japan Meteorological Agency (JMA) and the Joint Typhoon Warning Center (JTWC) noted the persistence of an area of atmospheric convection about 425 nautical miles (787 km; 489 mi) south-southeast of Guam.[5] The convection's nearby environment exhibited low vertical wind shear and warm 29–30 °C (84–86 °F) sea surface temperatures; ideal conditions for tropical cyclogenesis.[6] The JMA assessed the area of convection to have developed into a tropical depression on May 29 at 06:00 UTC around 06°N 136°E / 6°N 136°E.[7] The PAGASA made a similar assessment in a Tropical Cyclone Advisory issued at 15:00 UTC.[8] The JTWC later followed with their own assessment, identifying the center of the newly developed tropical depression approximately 35 nautical miles (65 km; 40 mi) south-southeast of Angaur, Palau and assigning the designation 04W.[9] As the system tracked westward, it entered the Philippine Area of Responsibility at 01:00 PHT (17:00 UTC).[10] The PAGASA then named the storm Dante in its first Tropical Cyclone Bulletin for the storm.[11]
Choi-wan intensified further in the Philippine Sea and the JTWC had determined that the depression strengthened into a tropical storm.[12][13] Later on, the Japan Meteorological Agency also upgraded the system into a tropical storm, and the storm was then named Choi-wan.[14] Choi-wan's center was exposed due to a tropical upper tropospheric trough from the northeast, inducing shear on the system.[15] The system continued to move northwestward before taking a west-northwestward track while continuing to struggle from moderate shear.[16] At 20:30 PHT (01:30 UTC), Choi-wan struck Sulat, Eastern Samar as a minimal tropical storm.[17] Midway through its transit through the Philippines, the JTWC then downgraded it into a tropical depression.[18][16]
It then made a second landfall on the municipality of Cataingan on the island of Masbate at 17:00 UTC on June 1[19] before it made another landfall in Balud at 19:30 UTC, still in the province.[20] It traversed the Sibuyan Sea then made a fourth landfall in the island of Romblon, Romblon at 00:00 UTC on the next day.[20] It crossed the Romblon Pass before making a fifth landfall in the municipality of San Agustin, fifty minutes after the previous one, still in the province.[20] Choi-wan then headed northwest while struggling to reorganize under the waters of the Tablas Strait, and then making a sixth landfall in Pola, Oriental Mindoro at 06:00 UTC.[20] It traversed the island of Mindoro with the system being disorganized again before exiting into the Verde Island Passage. Choi-wan then made a seventh landfall in Marincaban Island, Tingloy, Batangas at 11:20 UTC.[20] Continuing to move northwestward, the system made an eighth and final landfall in the Calatagan Peninsula in Batangas at 12:00 UTC on June 2 before exiting back into the South China Sea.[21] Despite the system being predicted to dissipate in the area, warm sea surface temperatures aided Choi-wan to restrengthen to a tropical storm at 03:00 UTC on the next day.[22]
A large high-pressure area in the central Pacific Ocean and an anticyclone over China turned the system north-northeastward, with the storm exiting the Philippine Area of Responsibility at 18:00 UTC.[23] Dry air yet again impacted the storm, with Choi-wan's convection being displaced to the west as it approached Taiwan and as a result, the storm weakened again to a tropical depression per the estimates of the JTWC[citation needed] and the PAGASA.[24] At 08:00 UTC on June 4, Choi-wan reentered the PAR before the system started to merge with an existing meiyu front which extends from China to the Japanese Islands[25] and at the same time, passing to the south of Taiwan.[26] At 1:00 UTC, the system re-exited the PAR for the second and final time[25] as it headed north-northeastward.[citation needed] While passing through the Ryukyu Islands, the JMA issued their final warning on Choi-wan as it transitioned to an extratropical storm[27] as it was still embedded in the front.[citation needed]
As Choi-wan (known locally as Dante) approached the Philippines, Tropical Cyclone Warning Signal (TCWS) #1 was issued in most of Luzon, the Visayas and Mindanao on May 31.[28] The next day, as Dante came closer to landfall, TCWS #2 was issued across a stretch of the eastern Philippines extending northward from Biliran and Samar to Quezon.[29] Before the landfalls of Choi-wan, the NDRRMC conducted a risk assessment for the approaching storm on May 31 while over ₱1.105 billion worth of standby funds were dispersed by the country's Social Welfare and Development department for the evacuees.[30] The Philippine Institute of Volcanology and Seismology (PHIVOLCS), in the other hand, issued an advisory for possible lahar on June 1 for the Mayon Volcano.[31] At least 604 people were forced to take shelter in evacuation centers in Davao City.[32] Elsewhere, classes were suspended and workplaces closed in Sorsogon on June 1 and 2.[33] 500 families in Agusan del Norte were forced to flee their homes as flash floods swept across the region.[34] A total of 45,000 people were impacted in the southwestern Philippines, while 12,000 were safely evacuated.[2] In Western Visayas, 895 people were evacuated on June 2.[3] Within Negros Occidental, sea travel was suspended and citizens reported flooding.[35] A preemptive evacuation were ordered on Albay's landslide, flood and lahar-prone areas on the same day.[36] The province of Ilocos Norte in Northern Luzon were placed on heightened alert, also on the same day, following Choi-wan's approach as the storm progressed in the South China Sea.[37]
In Mindanao, heavy rains caused flash floods and landslides from May 29 to June 1, affecting at least 2,642 people and destroying crops.[38][32] Floods killed a girl and left her father missing in South Cotabato, and drowned a man in Davao del Sur. A landslide killed a baby in Davao de Oro.[32] Damage to agriculture in Mindanao was valued at ₱14.6 million (US$305,000).[39] A pick-up truck was swept up by floods and both of its two passengers were left missing, although they were later found alive with the truck being damaged beyond recognition.[35] Around 4,813 citizens were displaced in Agusan del Norte from Choi-wan.[4] Choi-wan caused ₱307.2 million in damage (US$6.39 million) to infrastructure and in the agricultural industry across both Visayas and Mindanao throughout its path on June 1–2.[40] Choi-wan later scraped the coastline of Batangas Province in Luzon, causing minimal impact, before exiting into the coastal waters near Oriental Mindoro.[41] 2 people, a 28-year-old man and 32-year-old woman, died in Oriental Mindoro after being struck by lightning, the man dying immediately and the woman dying on arrival to the hospital due to her injuries.[42] A 19-year-old teen died in Occidental Mindoro after also being struck by lightning in San Jose.[43] 11 people in total died across the Philippines, while at least 2 are still missing as of June 6.[1]
The Central Weather Bureau of Taiwan issued land wind warnings across the country on June 3 as Choi-wan approached the country from the southwest.[44] Heavy rain alerts were also issued for 15 counties as Choi-wan interacted with a front which was also delivering rainfall to the country.[44] Roads in Greater Taipei were flooded and became impassable, while trees collapsed under the dampened soil.[45] 234 mm (9.2 in) of rain fell in Taipei within just three hours, while an estimated 300 mm (12 in) of rain fell near the National Taiwan University.[45] The districts of Daan, Wenshan, Nangang, Neihu, and Xinyi in Taipei all reported over 100 mm (3.9 in) of rain due to the combination of the frontal system and Choi-wan, according to Taipei Mayor Ko Wen-je.[46] Wind warnings related to Choi-wan were lifted on June 4 as the storm weakened to a tropical depression, although rain warnings remained in effect as the unrelated frontal system continued to produce heavy rainfall.[26]