2023 Pacific typhoon season

Tropical depression (JMA)
Duration	April 10 – April 13
Peak intensity	55 km/h (35 mph) (10-min); 1004 hPa (mbar)

The JMA first noted a low-pressure area in the Philippine Sea on April 7.[9] A strong convection to the north of the system's low-level circulation center (LLCC) prompted the JTWC to first issue a Tropical Cyclone Formation Alert (TCFA) on the disturbance as it tracked west-northwestwards into a favorable environment for further development.[10] Later that day, the JMA and the PAGASA classified the storm as a tropical depression.[11][12] As the storm formed within the Philippine Area of Responsibility (PAR), the depression received the name Amang.[12]

Amang made its first landfall over Panganiban, Catanduanes around 23:00 PHT (15:00 UTC) on April 11.[13] Later the next day, the PAGASA reported that Amang had made a second landfall in Presentacion, Camarines Sur and later made its third landfall in Lagonoy, Camarines Sur.[14] Upon land interaction, the JTWC canceled its TCFA, stating that Amang had reached more unfavorable conditions including dry air and wind shear.[15] PAGASA downgraded the storm to a low on April 13.[16]

Agricultural damages caused by the storm were estimated at ₱50.84 million (US$923 thousand), affecting 1,569 farmers and 1,330 ha (3,300 acres) of land.[17] 1,918 passengers were stranded in the Bicol Region following sea travel suspensions.[18] On April 13, classes up to senior high school in 19 areas were suspended due to bad weather, along with pre-elementary classes in areas under Signal No. 1.[19]

Tropical storm (JMA)
Tropical storm (SSHWS)
Duration	April 19 – April 22
Peak intensity	85 km/h (50 mph) (10-min); 996 hPa (mbar)

An area of convection monitored by the JTWC spawned south-southeast of Pohnpei on April 18.[20] The JMA later classified the disturbance as a tropical depression the following day,[21] before the JTWC followed suit and designated the system 01W.[22] On April 20, the depression further intensified to a tropical storm, according to the JTWC,[23] after convection and rainbands strengthened over the LLCC.[24] The JMA subsequently upgraded its status by 6:00 UTC, and gave the name Sanvu to the storm.[25]

After reaching its peak intensity early on April 21, Sanvu began to weaken afterward due to clusters of convection on its northeast quadrant absorbing its energy.[26] By April 22, Sanvu's poor, ragged structure of its circulation center prompted the JTWC to cease issuing bulletins on the storm as it was downgraded to a tropical depression.[27] The JMA cancelled advisories on the storm the same day as well.[28] The JMA tracked the system until 00:00 UTC of April 25.[29] The JTWC reported that Sanvu's remnants had dissipated on April 26.[30]

Violent typhoon (JMA)
Category 5 super typhoon (SSHWS)
Duration	May 19 – June 2
Peak intensity	215 km/h (130 mph) (10-min); 900 hPa (mbar)

On May 17, a weak LLCC located 865 km (535 mi) south of Guam was marked by the JTWC.[31] Thunderstorms around the LLCC soon became very wide and organization had improved,[32] before the JMA upgraded the system to a tropical depression on May 19.[33] The JTWC followed suit on May 20 after the depression had strengthened from warm sea surface temperatures and outflow, designating it 02W.[34] The same day, the depression became a tropical storm, receiving the name Mawar.[35] The JMA further upgraded the storm to severe tropical storm status at 00:00 UTC of May 21,[36] as the deep convection in the central dense overcast (CDO) completely obscured the LLCC.[37] Both the JMA and JTWC upgraded Mawar to a typhoon on the same day.[38][39] Mawar further became a super typhoon and underwent an eyewall replacement cycle.[40][41] During May 24, the center of Mawar passed through the northern tip of Guam, and slightly weakened.[42][43]

Soon afterwards, Mawar reached its peak intensity, attaining 1-minute sustained winds of 295 km/h (185 mph), equivalent to Category 5 strength on the Saffir–Simpson hurricane wind scale,[44] and 10-minute sustained winds of 215 km/h (130 mph) along with the barometric pressure of 900 hPa (26.58 inHg).[45] Mawar entered the PAR, which PAGASA assigned it the name Betty.[46] Mawar slightly weakened moving around the southwestern edge of the subtropical high.[47] As a result, Mawar weakened into a severe tropical storm as the JMA reported on May 31,[48] before exiting the PAR on June 1.[49] Mawar became a tropical storm on June 2, as it approached Okinawa.[50] On June 3, Mawar transitioned into an extratropical cyclone south of Honshu, as it moved towards the open Pacific.[51]

Power outages began affecting parts of Guam on May 22 as winds from Mawar intensified.[52] Guam International Airport also recorded winds up to 104.7 miles per hour (168.5 km/h) as Mawar impacted the island.[53][54] Mawar passed north of the island as a Category 4-equivalent typhoon on May 24, bringing hurricane-force winds and heavy rain marking as the strongest storm to affect the island since Typhoon Pongsona in 2002.[55][56] Two men are presumed dead after going missing in the waters off Guam; additionally, one death related to the storm has been reported in Taiwan.[57] Mawar caused one death, one minor injury, and damage worth ₱201,696 (US$3,584) as it passed close to the eastern Philippines.[58] Heavy rain in parts of Japan killed two people and left four people missing.[59] At least 8,900 homes experienced power outages in Japan. Total damages from Mawar are estimated to reach $250 million USD.[60]

Typhoon (JMA)
Category 2 typhoon (SSHWS)
Duration	June 6 – June 12
Peak intensity	150 km/h (90 mph) (10-min); 960 hPa (mbar)

In the first weeks of June, a low-pressure area formed north of Palau, with the JTWC designating the system as Invest 98W, for a potential tropical cyclone development. JTWC later issued a Tropical Cyclone Formation Alert regarding with the system. The low-pressure area north of Palau then developed into a tropical depression late on June 5.[61] At the following day, it intensified and entered the Philippine Area of Responsibility, prompting the PAGASA to name it as Chedeng at 08:00 UTC.[62] The JTWC later followed suit and designated it as 03W, when the system had possessed nascent bands spiraling in all quadrants.[63]

At 20:00 UTC, Chedeng was upgraded into a tropical storm, attaining the name Guchol. Guchol slightly intensified and later became a strong Category 2 typhoon in the Philippine Sea with its peak intensity of 10-minute sustained winds of 150 km/h (90 mph), but the cold wake from Typhoon Mawar kept it from intensifying any further. As Guchol (Chedeng) exited the PAR, it weakened into a severe tropical storm, and continued northeastwards, avoiding the Japanese archipelago. It then became extratropical on June 12.

Guchol had minimal impact. However, it enhanced the southwest monsoon during its presence inside the PAR, resulting in widespread heavy rains over the western portions of Luzon.[64]

Severe tropical storm (JMA)
Category 2 typhoon (SSHWS)
Duration	July 13 – July 18
Peak intensity	110 km/h (70 mph) (10-min); 970 hPa (mbar)

On July 12, an area of low-pressure was noted off the coast of Aurora, Philippines. JMA later recognized the formation of a tropical depression.[65] PAGASA later named the system Dodong as it is inside Philippine Area of Responsibility.[66] It made its first landfall in Dinapigue, Aurora and continued to cross over Cagayan and Isabela. JTWC later designated for the now-tropical depression as 04W.[67] Prior exiting PAR, JMA subsequently named Talim as it intensified into a tropical storm.[68][69][70] The system had a broad LLCC with deep convection persisting along the western and southern periphery.[71] Talim continues to intensify in the South China Sea, later being strengthen into a severe tropical storm as it moves westward within a favorable environment being offset by equatorward outflow. JTWC later upgraded into a Category 2-equivalent typhoon with winds of around 155 km/h (100 mph).[72][73] Talim made its second landfall in Zhanjiang, Guangdong, with winds of 136 km/h (85 mph) on July 17. As it moved further inland, Talim rapidly weakened. Shortly after the landfall, the JTWC discontinued warnings on the system before it dissipated on the next day.[74]

Winds from Talim enhanced the East Asian monsoon over the Philippines and brought heavy rainfall and gusty conditions over the country as it neared Luzon.[75] Classes in three cities and in Cagayan were suspended as the storm crossed Luzon.[76] Agricultural damages are estimated by the NDRRMC at ₱199 million, with infrastructural damages estimated at ₱100 million. In total, the NDRRMC estimates at least ₱299 million (US$5.75 million) in damages due to Talim. Overall, the storm was responsible for 3 deaths.[77] In Vietnam, Talim also caused over 20.7 billion đồng (US$874,782) in damages to properties.[78]

Very strong typhoon (JMA)
Category 4 super typhoon (SSHWS)
Duration	July 20 – July 30
Peak intensity	185 km/h (115 mph) (10-min); 925 hPa (mbar)

On July 19, JMA began tracking a low pressure area in the Philippine Sea, east of Mindanao.[79] The agency noted its formation into a tropical depression by July 20. JTWC then released a TCFA on the storm later that day.[80] On July 21, the system intensified into a tropical storm and was named Doksuri. The PAGASA also noted the storm's formation and locally named it Egay.[81][82] The JTWC subsequently initiated advisories on the system and classified it as 05W.[83] Doksuri slightly intensified as it tracked northwestward across the following day.[83][84][85] At 12:00 UTC on July 23, Doksuri began to rapidly intensify as it reached super typhoon status over the Philippine Sea.[86][87] Doksuri traversed through the extreme northern Philippines across the night, weakening into a typhoon and later making landfall at Camiguin Island and later in Fuga Island in Aparri, Cagayan.[88][89] Doksuri made a third landfall over Dalupiri Island on July 26, moving very slowly as it did so, dropping massive amounts of rainfall over the Ilocos Region and other parts of Northern Luzon.[90] Doksuri left the PAR at around 10:00 PHT (02:00 UTC) on July 27.[91] Doksuri then began to ensue another round of rapid intensification, forming a pinhole eye[92] Doksuri moved northwestward and subsequently made its fourth and final landfall in Jinjiang, Fujian, with two-minute sustained winds of 180 km/h (50 m/s) on July 28.[93] Doksuri rapidly weakened once inland and dissipated shortly thereafter.[94]

Overall, the typhoon was responsible for 137 deaths, 46 missing and 285 injured,[95][96] including 27 people on board the MB Aya Express who were killed when the pump boat capsized and caused $15.7 billion in damage across several countries.[97] The old Quirino bridge in Bantay, Ilocos Sur was severely damaged due to the powerful waters from Abra River, which caused the bridge to surge over the main body, submerging the titles "ONE ILOCOS SUR" inscription that adorned it.[98]

Very strong typhoon (JMA)
Category 4 typhoon (SSHWS)
Duration	July 26 – August 11
Peak intensity	175 km/h (110 mph) (10-min); 930 hPa (mbar)

On July 26, the JMA announced the formation of a low-pressure area in the Pacific Ocean. The JMA started warning the system, declaring it a tropical depression.[99][100] Analysis from the JMA indicated that the system was in a favorable environment for development, with warm sea surface temperatures and low vertical wind shear.[101] The JMA and the JTWC upgraded the system to a tropical storm,[102] with the JMA assigning the name Khanun for the system.[103] Khanun consolidating LLCC with formative convective banding and deep convection over the eastern semicircle.[104] Khanun entered the PAR around 03:00 UTC (11:00 PHT) on July 29, and was named Falcon by the PAGASA.[105] Over 24 hours, its maximum sustained wind speeds grew by 130 km/h (80 mph) and eventually reached a peak of 220 km/h (140 mph), equivalent to Category 4 status on the Saffir–Simpson scale.[106][107] Khanun left the PAR at around 03:00 PHT (19:00 UTC) on August 1.[108] Satellite imagery showed a consolidating LLCC with formative convective banding and deep convection over the northern semicircle.[109] Around 00:00 UTC on August 10, Khanun made landfall on Geojedo Islands in South Korea with winds of 85 km/h (50 mph).[110][111] The JMA continued to monitor Khanun as a tropical cyclone until early on August 11.[112]

As of August 18, 13 deaths were reported and 16 are reported to have gone missing following the typhoon,[113] another 115 remain injured, and damage totaled at US$98.1 million.[114] At least 160,000 homes lost power across the island chain.[115][116] Khanun became the first to pass through the Korean Peninsula from south to north since recordkeeping began in 1951.[117] The Korean Central Television reported wind speeds of more than 18 km/h (11 mph) with averaging 181 mm (7.1 in) in Kangwon Province.[118] Although Khanun did not directly affect the Philippines, both Khanun and Typhoon Doksuri enhanced the monsoon for several days, which caused severe flooding throughout the country.[119]

Very strong typhoon (JMA)
Category 4 typhoon (SSHWS)
Duration	August 5 – August 17
Peak intensity	165 km/h (105 mph) (10-min); 940 hPa (mbar)

On August 5, the JMA reported that a low-pressure area had formed east-northeast of Iwo Jima. Deep convection shifted towards the southeastern semicircle of the circulation, while the still-poorly defined center.[120][121] Environmental conditions were assessed as being marginally conducive for tropical cyclogenesis, with warm sea surface temperatures (SST) near 29–30 °C (84–86 °F) and low vertical wind shear, and good equatorward outflow.[122] At the same time, the JMA upgraded it to a tropical depression, before the JTWC issued a TCFA on the system.[123][124] Later that day, the agency upgraded to a tropical storm,[125] with the JMA assigning the name Lan for the system.[126] Lan continued to strengthen as it turned more westward under the influence of the SST and weak vertical wind shear, the JMA upgraded Lan to a severe tropical storm at 06:00 UTC on August 9 as its maximum sustained winds increased to 95 km/h (60 mph).[127] Lan began to intensify more quickly, reaching typhoon status.[128][129] The JTWC upgraded it to Category 4-equivalent typhoon on August 11 after Dvorak estimates indicated winds of 215 km/h (130 mph).[130] Lan was rapidly decaying as the storm struggled to −60 °C (−76 °F) the cold ring that surrounded the eye.[131] The storm maintained its overall convective structure, but the waters beneath the cyclone cooled, prompting a quick weakening trend.[132][133] Around 19:00 UTC on August 14, Lan made landfall near Cape Shionomisaki in Japan.[134] Lan emerged back over the southern Sea of Japan.[135] The JMA issued its last advisory on Lan, and declared it an extratropical low on August 17.[136]

The JMA issued purple heavy rain—the second highest level on a four-tier scale—and landslide warnings for parts of Kyoto Prefecture in Kansai region and Iwate Prefecture in Tōhoku region as of late August 14.[137] Typhoon Lan caused widespread damage. In addition to causing landslides and flooding, the storm also uprooted trees and damaged electrical lines. At least 100,000 homes are without power, and more than 237,000 individuals have been forced from their homes.[138] One person has been reported dead and 64 are reported to have remained injured following the typhoon.[139][140]

Typhoon (JMA)
Category 2 typhoon (SSHWS)
Duration	August 12 (entered basin) – August 21
Peak intensity	150 km/h (90 mph) (10-min); 975 hPa (mbar)

On August 11, a weakening Hurricane Dora moved into the basin from the Central Pacific basin.[141] At 00:00 UTC, August 12, the JMA and the JTWC initiated advisories on Dora, declaring that it had just crossed the International Date Line and classifying it as a typhoon.[142] The cloud tops further warmed and its eye vanished from satellite imagery.[143] Dora showed significant deterioration along the system's northern flank.[144] Dora became increasingly sheared by early August 13, interacting with an upper-level trough.[145] Vertical wind shear exceeded 35 km/h (25 mph). Further decay in the organization of the storm's deep convection caused Dora to be downgraded to a tropical storm.[146] With Dora's ragged center, the system remained disorganized, as wind shear was becoming displaced to the east.[147][148] By the early hours of August 15, both agencies issued their final warnings on Dora; its LLCC further became broad and exposed.[149][150] The JMA, however, continued to monitor the system until it was last noted on 18:00 UTC of August 21.

Severe tropical storm (JMA)
Category 1 typhoon (SSHWS)
Duration	August 21 – August 29
Peak intensity	95 km/h (60 mph) (10-min); 985 hPa (mbar)

On August 21, the JMA started tracking a tropical depression in the open Western Pacific. The JTWC then followed suit on August 23 by upgrading the system into a tropical depression, and designating it as 08W. The JMA later upgraded the system into a tropical storm on August 24, receiving the name Damrey, with the JTWC following suit later on August 25. It gradually intensified as it moves northward, becoming a severe tropical storm and Category 1-equivalent typhoon, by the JMA and the JTWC, respectively, well east of Japan, on August 27. It turned post-tropical on August 29.

The remnants of the storm delivered high winds in Alaska, with a 69 mph (111 km/h) wind gust in Potter Marsh and 43 mph (69 km/h) gust at Ted Stevens Anchorage International Airport. High winds hit the Anchorage Bowl on Thursday, knocking out power to thousands as the remnants blow in the Southeastern Alaska. Strong winds downed trees throughout town that hit power lines and caused outages.[151]

Violent typhoon (JMA)
Category 4 super typhoon (SSHWS)
Duration	August 22 – September 3
Peak intensity	195 km/h (120 mph) (10-min); 920 hPa (mbar)

On August 20, an area of convection east of Taiwan began moving southwestwards with little organization over its center. The PAGASA initially expected the system to not develop into a tropical cyclone,[152] but later upgraded it into a tropical depression the next day, and was given the local name of Goring,[153] it was also given a Tropical Cyclone Formation Alert by the JTWC, designated as 09W. Goring then moved generally north-northwestwards across the Philippine Sea. On August 24, Goring was upgraded to a tropical storm by the JTWC, with the JMA following suit a few hours later at 06:00 UTC, receiving the name Saola. Saola continued to intensify and began to move southwestwards over the Philippine Sea east of the Batanes Islands. A few hours later, the JTWC upgraded Saola into a typhoon, with the JMA upgrading the system to a severe tropical storm shortly thereafter. Saola began in a process of rapid intensification where it reached into a category-4 typhoon on August 27.[154]

After it executed a south-southeastward turn over the Philippine Sea. Saola weaken back into a category-2 typhoon. However, on August 29, it then explosive intensified again into a high-end Category 4 super typhoon while crossing the northwestern boundaries of the Philippine Area of Responsibility. Saola remained as a powerful super typhoon while approaching Hong Kong and China. Prior to the arrival of the typhoon, Hong Kong Observatory issued Hurricane Signal No. 10 at 20:15 HKT, September 1, the first time in 5 years since Typhoon Mangkhut (Ompong) in 2018.[155] It passed south of Macau and Hong Kong, battering gusty winds and heavy rains. Saola weakened into Category 3 before making landfall over Guangdong, China.[156] As it moves inland, Saola weakened into severe tropical storm and later tropical depression by September 2 before it dissipated on September 3.

Very strong typhoon (JMA)
Category 3 typhoon (SSHWS)
Duration	August 27 – September 6
Peak intensity	155 km/h (100 mph) (10-min); 955 hPa (mbar)

Whilst Typhoon Saola was exhibiting a counter-clockwise loop east of the Philippines, a new broad low pressure area developed into a tropical depression on August 27, near the Northern Mariana Islands, while slowly drifting westward. On August 28, the JMA subsequently upgraded the system into a tropical storm, naming it Haikui. The JTWC began initiating advisories thereafter and was designated as 10W. Haikui then rapidly strengthened into the severe tropical storm category a few minutes later. As it moved west-northwest, Haikui entered the Philippine area of responsibility at around 21:00 PHT (13:00 UTC) and was given the domestic name Hanna.

Haikui then maintained its severe tropical storm status for about a day while moving generally westwards across the Philippine Sea, before finally reaching typhoon status on September 1. Haikui then continued westwards over the Philippine Sea with little change in intensity but later intensified into a Category 2-equivalent typhoon a day later. Typhoon Haikui then began an episode of rapid intensification by September 3 at least 18 hours before landfall, becoming a strong Category 3 typhoon. Haikui struck Taitung County, Taiwan as a Category 3, becoming the first storm to hit mainland Taiwan for the first time in 4 years after Severe Tropical Storm Bailu (Ineng) and the first Category 3+ typhoon to hit the island since Typhoon Megi (Helen) in 2016.[157] The collision between Typhoon Haikui & the mountain ranges of Taiwan considerably wrecked the structure of the storm and made it weaken back into a minimal Category 1 typhoon by the time it exited the landmass of the island in the evening. Haikui then moved erratically over the next few hours, heading eastwards and making a second landfall in Kaohsiung, Taiwan.[158] Haikui then continued back on its westward course a few hours later. The typhoon left the Philippine Area of Responsibility on September 4, as it left the Taiwanese landmass. The JMA then downgraded Haikui back into a severe tropical storm as its circulation became degraded after the landfall.

Though not making any direct landfall in the Philippines, Typhoon Haikui (locally known as Hanna) enhanced the southwest monsoon along with Typhoon Saola, causing heavy rainfall and strong winds in many areas especially in Luzon, and causing one death.[159] The PAGASA raised Signal #1 for the Batanes and Babuyan Islands as Haikui approached and its track, initially expected to make landfall in Eastern China, shifted southwards over time.

On September 5, Typhoon Haikui made landfall along the coast of Dongshan County, Fujian.[160] Rainstorm to heavy rainstorm occurred in coastal areas of Fujian,[161] causing the death of two firefighters.[162]

On September 7, the remnants of Typhoon Haikui brought record breaking rainfall to Hong Kong. Hong Kong Observatory recorded 158 millimeters of rain between 11pm and midnight local time, the highest hourly rainfall rate since records began in 1884.[163] Some parts of the city even accumulated over 900 mm of rainfall within just 24 hours.[164] Four people were killed in Hong Kong as a result of the flash floods.[165] Other parts of the Pearl River Delta, including Shenzhen and Macau, were also severely impacted.

Severe tropical storm (JMA)
Tropical storm (SSHWS)
Duration	August 29 – September 6
Peak intensity	95 km/h (60 mph) (10-min); 992 hPa (mbar)

A low pressure area located far east of Guam developed on August 29, indicating that the system is in a favorable environment and low windshear. Over the next day, the JTWC started issuing advisories as it steadily upgrading into a tropical depression, which designated as 11W.

Slowly intensifying while moving generally northwest, the system developed into a tropical storm, as announced by JTWC, on August 30. JMA followed suit shortly thereafter, giving it the name Kirogi. The storm slightly strengthened to a severe tropical storm. In the first month of September, JMA announced that it weakened back into a tropical storm before rapidly weakening on September 2. Its remnants meandered around Japan and interacted with Tropical Storm Yun-yeung for a few days before dissipating on September 6.

Tropical storm (JMA)
Tropical storm (SSHWS)
Duration	September 4 – September 8
Peak intensity	85 km/h (50 mph) (10-min); 996 hPa (mbar)

From the bands of Typhoon Haikui, an area of low pressure formed in the Philippine Sea in early September. The low-pressure area intensified into a tropical depression on September 4 and was later named Ineng by the PAGASA. A day later, the Japan Meteorological Agency (JMA) upgraded Ineng into a tropical storm and was given the name Yun-yeung, which replaced Kai-tak. Shortly after being named, on September 6, Yun-yeung left the PAR at around 06:00 PHT (22:00 UTC). Yun-yeung continued to move northward slowly as it approaches central and eastern Japan. The JMA last noted Yun-yeung on 18:00 UTC of September 8.

Yun-yeung brought heavy rain across wide areas of Japan, prompting warnings over the risk of flooding and mudslides. Some train lines were impacted in the Kanto region on Friday. JR East suspended some lines and limited express trains on Friday, and multiple lines are experiencing delays.[166]

Tropical depression (JMA)
Tropical depression (SSHWS)
Duration	September 24 – September 27
Peak intensity	<55 km/h (35 mph) (10-min); 1000 hPa (mbar)

An area of low-pressure formed near the Southern Philippines. On September 24, JMA recognized it as a tropical depression as it tracked westward. Around the same day, JTWC designated the system as 13W. It was tracking north-northwestward toward the Vietnam coast.[167] Although the depression was within favorable conditions, it remained as a weak depression and made landfall at Da Nang, Vietnam. The JMA last tracked the system on September 27.

Flooding occurred in Da Nang, Quảng Trị, Quảng Bình, Bình Định, Thanh Hóa, Nghệ An and Hà Tĩnh.[168]

Very strong typhoon (JMA)
Category 4 typhoon (SSHWS)
Duration	September 29 – October 10
Peak intensity	165 km/h (105 mph) (10-min); 940 hPa (mbar)

On September 27, a low-pressure system formed near Guam, with the JTWC indicating the potential development of a tropical cyclone in the coming days. It moved westward into the Philippine Sea until it entered the Philippine Area of Responsibility, where it was later upgraded into a tropical depression and gained the name Jenny by the PAGASA. A Tropical Cyclone Formation Alert was then issued for Jenny as it began to show signs of further organization. Hours later, JTWC gave its identifier 14W at 13:00 UTC (21:00 PHT). On September 28, JMA upgraded 14W into a tropical storm and attained the name Koinu, which replaced the name Tembin. PAGASA then later followed suit at their 5 AM PHT weather bulletin, also upgrading Jenny into a tropical storm; a few hours later, JTWC followed suit.

Koinu moved west-northwestward in the Philippine Sea whilst having its low-level circulation exposed due to wind shear. Koinu then later organized further, and by the next day, the JMA upgraded Koinu into a severe tropical storm. As usual, the PAGASA followed suit a few hours later. Koinu later gradually intensified into a Category 1 typhoon by the JTWC. The other agencies also followed suit in upgrading Koinu into a typhoon as an eye began to form. Koinu then began a period of rapid intensification by the evening of October 1 into the early morning hours, intensifying to become a Category 3 typhoon whilst it developed a clear eye as it moved east of Cagayan before weakening slightly. Koinu weakened to Category 2 strength yet rebounded its intensity and reached Category 4 whilst nearing Taiwan and moving west-northwestward. Koinu passed dangerously close to Lanyu, and making its first landfall on mainland Hengchun, Taiwan, later weakening into a Category 3 storm as it did soon On 4 October 2023, 212 mph wind gusts were recorded In Orchid Island, Taiwan At 9:53am (ET), the fastest wind gust Taiwan has experienced.

[169] Koinu then weakened into a Category 1 after slamming into Taiwan and later exited the PAR into the South China Sea. Contrary to forecasts, Koinu unexpectedly restrengthened back into a Category 2, reforming a clear visible eye surrounded by a powerful eyewall. Koinu further intensified, regaining Category 3 status east of Guangdong.

As Typhoon Koinu (Jenny) approached the Northern Philippines including Extreme Northern Luzon, the PAGASA began issuing warnings for parts of Northern Luzon, and a few days later, Signal #3 was raised on Itbayat, Batanes as the typhoon brought showers and gusty winds to the islands.[170]

Violent typhoon (JMA)
Category 5 super typhoon (SSHWS)
Duration	October 6 – October 14
Peak intensity	215 km/h (130 mph) (10-min); 900 hPa (mbar)

A tropical depression was marked by the JMA on October 6.[171] The following day, it was designated 15W by the JTWC when flaring convection around its LLCC was persistent enough.[172] Although it was disorganized, the system continued to consolidate, and was subsequently upgraded to Tropical Storm Bolaven.[173] Bolaven then began developing poleward outflow into the southern edge of a tropical upper tropospheric trough cell, with vortical hot towers persisting over the western quadrant.[174] A CDO was formed on October 8, as Bolaven steered westward.[175] That same day, the JMA upgraded Bolaven to a severe tropical storm.[176] On October 10, both the JMA and JTWC upgraded Bolaven to a typhoon.[177][178] Bolaven then became a super typhoon after it underwent explosive intensification in which it went from a 150 km/h (90 mph) Category 1-equivalent typhoon to a 260 km/h (160 mph) Category 5-equivalent super typhoon in a 12‑hour period ending at 00:00 UTC on October 11, an increase of 110 km/h (70 mph),[179] after leaving the Mariana Islands. Bolaven also displayed its eye with the stadium effect.[180] Thereafter, Bolaven began to weaken from increased wind shear.[181] Unfavorable conditions began to rapidly weaken Bolaven into below super typhoon strength on October 13, recurving northeastward.[182] With cold air advection taking place, Bolaven began its extratropical transition on October 14, ceasing the issuance of bulletins from the JTWC.[183]

On October 10, Bolaven moved through the Northern Marianas Islands,[184] while the archipelago was still recovering from the damaging passage of Typhoon Mawar five months earlier.[185] Saipan International Airport recorded sustained winds of 89 km/h (55 mph), along with typhoon-force gusts of 126 km/h (78 mph), while in Guam, wind gusts of 80 km/h (49 mph) at Antonio B. Won Pat International Airport were recorded.[184] The high winds knocked down trees and cut the electricity for the islands of Tinian and Rota, while parts of Saipan also lost power.[186]

Tropical storm (JMA)
Tropical storm (SSHWS)
Duration	October 17 – October 20
Peak intensity	75 km/h (45 mph) (10-min); 1002 hPa (mbar)

On October 13, a low-pressure area developed to the west of the Philippines.[187] Deep convection broadened over its partially-exposed LLCC with weak rainbands. Due to the system being over warm waters and low vertical wind shear, a TCFA was announced on October 16.[188] The following day, the system was marked as a tropical depression by the JMA, east of Vietnam.[189] The JTWC subsequently followed suit, designating it as 16W.[190] Infrared satellite imagery depicted a CDO obscuring the circulation of the ragged tropical depression.[191] It was upgraded to a tropical storm later the next day, receiving the name Sanba.[192] A deep-layer southerly flow began to significantly influence the storm after shearing upper and mid-level clouds.[193] Sanba made landfall on Hainan on October 19.[194] Sanba accelerated north-northeastward, while aided by warm waters, with overshooting tops scattering radially aloft.[195] With an exposed LLCC, Sanba weakened into a tropical depression on October 20.[196]

Many of the tropical depressions of the season failed to intensify into tropical storms, or even be numbered.

A tropical depression over Palawan on May 5.

• According to the JMA, a tropical depression formed to the east of Singapore on March 4.[197] It was designated 98S by the JTWC shortly afterwards, due to the agency analyzing the system as being located within the Southern Hemisphere.[198] The system was last noted on March 7.[199] 50,000 people were affected in Malaysia from the floods produced by the system, which also killed four people.[200]
• On May 1, a tropical disturbance persisted around 740 km (460 mi) east of Davao City and had fragmented but organized rainbands to the north and west of its circulation center.[201] The convection continued to broaden as it wrapped the disorganized LLCC. However, land interaction with the Philippines and the system's weak structure hindered further development, despite being in favorable environmental conditions.[202] On May 5, the JMA classified the disturbance as a tropical depression.[203] However, dry air and a weak outflow aloft showed that the depression had very little development, all while tracking west-northwestward.[204] The depression later dissipated by May 7.[205][206]
• On June 7, the JMA detected a broad area of circulation associated with a tropical disturbance north of Hainan. The agency dubbed it a tropical depression shortly after. However, by the next day, the system moved over China and the circulation center began deteriorating. The system was last noted on 18:00 UTC of June 11. Persistent rainfall in Guangxi caused the Baisha River to flood multiple villages in Hepu County. Firefighters used boats to rescue residents trapped in their homes. A total of 2,603 people required evacuation.[207] On June 9, Vietnam's National Center for Hydrometeorological Forecasting (NCHMF) issued "Potential Tropical Depression Alert" in the Gulf of Tonkin, which warned the resurgence of this tropical depression but then discontinue monitoring on June 10.
• On August 3, a tropical depression formed to the west of Hainan. The system weakened on August 4.
• On August 19, a tropical depression formed to the southeast of Japan. The system dissipated on August 21.
• On September 3, a tropical depression formed before dissipating the next day due to high wind shear.
• On September 4, the JMA started tracking a depression that originated from the tail-end of Tropical Storm Kirogi. The system was last noted on 06:00 UTC of September 6.
• On September 10, a tropical depression formed near the Ryukyu Islands. It meandered around the area for a few days before turning south and then northwest toward Taiwan. The system dissipated on September 14.
• The JMA briefly tracked a tropical depression that persisted to the northeast of the Mariana Islands on September 12.

A tropical cyclone is named when it is judged to have 10-minute sustained windspeeds of 65 km/h (40 mph).[210] The JMA selected the names from a list of 140 names, that had been developed by the 14 members nations and territories of the ESCAP/WMO Typhoon Committee.[211] During the season, the names Yun-yeung and Koinu were used for the first time; they replaced the names Kai-tak and Tembin, which were retired after the 2017 season. Retired names, if any, will be announced by the WMO in 2024, though replacement names will be announced in 2025. The next 28 names on the naming list are listed here along with their international numeric designation, if they are used.

If a tropical cyclone enters the Western Pacific basin from the Eastern and Central Pacific basin (west of 180°E), it will retain the name assigned to it by the National Hurricane Center (NHC) and Central Pacific Hurricane Center (CPHC). The following storms were named in this manner.

• Dora (2308)

This season, PAGASA will use its own naming scheme for storms that develop in or enter their self-defined area of responsibility.[212] During this season, PAGASA is using the following list of names, that was last used during 2019 and will be used again in 2027, updated with replacements of retired names, if any.[212] All of the names are the same as in 2019 except Tamaraw and Ugong, which replaced the names Tisoy and Ursula after they were retired.[212]