The 2020 Pacific typhoon season was the first of a series of four below average Pacific typhoon seasons, and became the first with below-average tropical cyclone activity since 2014, with 23 named storms, 10 of which became typhoons and only 2 became super typhoons. This low activity was a consequence of La Niña that persisted from the summer of the year. It had the seventh-latest start in the basin on record, slightly behind 1973, and was the first to start that late since 2016. The first half of the season was unusually inactive, with only four systems, two named storms and one typhoon at the end of July. Additionally, the JTWC recorded no tropical cyclone development in the month of July, the first such occurrence since reliable records began. Despite that, this season featured Typhoon Goni, which made the strongest landfall worldwide in terms of 1-minute wind speed. The season ran throughout 2020, though most tropical cyclones typically develop between May and November. The season's first named tropical cyclone, Vongfong, developed on May 8, while the season's last named tropical cyclone, Krovanh, dissipated on December 24. However, the season's last system was an unnamed tropical depression which dissipated on December 29.
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 Japan Meteorological Agency (JMA) will name a tropical cyclone should it be judged to have 10-minute sustained wind speeds of at least 65 kilometers per hour (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 JMA. Tropical depressions that are monitored by the United States' Joint Typhoon Warning Center (JTWC) are given a number with a "W" suffix.
Seasonal forecasts
During the year several national meteorological services and scientific agencies forecast how many tropical cyclones, tropical storms, and typhoons will form during a season and/or how many tropical cyclones will affect a particular country. These agencies include the Tropical Storm Risk (TSR) Consortium of University College London, PAGASA and Taiwan's Central Weather Bureau. The first forecast for the year was released by PAGASA on January 22 predicting the first half of 2020, within its monthly seasonal climate outlook. The PAGASA predicts that only 0–4 tropical cyclones are expected to form or enter the Philippine Area of Responsibility between January and March, while 3–6 tropical cyclones are expected to form between April and June. This was due to the fact that the El Niño–Southern Oscillation was seeing neutral conditions across the Pacific, and could persist until midyear. On May 21, the TSR issued their extended-range forecast for 2020, forecasting tropical activity below the average normal, with 26 tropical storms, 15 typhoons and 8 intense typhoons. These numbers were supported by the current values from the Indian Ocean Dipole, the Accumulated Cyclone Energy index and the sea-surface temperatures in the Niño 3.75 region, leading to a stronger than normal trade windspeed throughout much of the Western Pacific.
On June 24, the PAGASA issued a climate forecast, predicting the number of tropical cyclones for the second half of the season. They predicted that 6–12 tropical cyclones are expected to form between the months of July and September, while 4–8 tropical cyclones are expected to form between the months of October and December. On July 9, TSR issued their forecast for the season, predicting a well-below average season with 26 named storms, 14 typhoons and only 7 intense typhoons. On August 6, TSR issued their third and final forecast for the season, lowering their numbers to 21 named storms, 13 typhoons and 5 intense typhoons. They mentioned that the 2020 season is expected to be one of the "least active typhoon seasons on record", with a predicted ACE index barely half of the normal and a 96% probability of being a below-average season.
Systems
Typhoon Vongfong (Ambo)
After 4 months of lull activity, A low-pressure area was first noted on May 9 by the JTWC near Micronesia and was given a medium chance of developing into a tropical cyclone. The following day, the JMA declared that it had developed into a tropical depression to the east of Mindanao, Philippines and was expected to slowly move west. On May 10, PAGASA later followed suit and named the depression Ambo.
The system began to slowly drift westwards throughout the following days, and on the next day, the JTWC upgraded Ambo to a tropical depression, designating it as 01W. The JMA upgraded 01W to a tropical storm and assigned it the first name of the year, Vongfong. Shortly after, the JTWC followed and upgraded the system to tropical storm intensity. A well-defined eye soon emerged on microwave satellite imagery as the storm's structure became further organized The eye became increasingly pronounced and contracted to less than 10 km (6.2 mi) in diameter as the storm's evolution became suggestive of rapid intensification. The JTWC assessed 1-minute sustained winds of 195 km/h (121 mph) at 21:00 UTC on May 13 shortly before the onset of an eyewall replacement cycle; Vongfong made landfall with this intensity over San Policarpo, Eastern Samar, at 04:15 UTC on May 14. Vongfong made six additional landfalls as it traversed the remainder of the Visayas into Luzon: Dalupiri Island; Capul Island; Ticao Island; Burias Island; San Andres, Quezon; and Real, Quezon. The prolonged interaction with land caused Vongfong to weaken, though the storm maintained a compact circulation amid otherwise favorable atmospheric conditions. On May 15, Vongfong downgraded back into a tropical storm and later tropical depression on the following day before dissipated over Bashi Channel on May 17.
Tropical Storm Nuri (Butchoy)
On June 10, the JMA began monitoring on a weak tropical depression that had developed to the east of the Philippine island of Samar in Visayas. During the next day, the PAGASA began tracking the system, giving the local name Butchoy. The storm then made its first landfall in Polillo Island in Quezon at 5:30 pm PHT, and making its second landfall in Infanta, Quezon shortly thereafter. Soon after, the JTWC issued a Tropical Cyclone Formation Alert for the storm. Afterwards, the JTWC officially upgraded Butchoy to a tropical depression, and designated it as 02W. With a favorable environment with low vertical wind shear, moderate equatorial outflow and 30–31 °C sea surface temperatures, Butchoy started to intensify in the South China Sea, becoming a tropical storm and receiving the name Nuri from the JMA later on the same day. Then, PAGASA issued their final warning on Nuri as it exited the Philippine Area of Responsibility. By the next day, Nuri intensified further and subsequently peaked in intensity, with the JMA analyzing the storm's peak winds of 75 kilometers per hour (47 mph). Six hours later, the JTWC upgraded Nuri to a tropical storm. However, later in the same day, the JTWC downgraded Nuri into a tropical depression, citing that the storm has drifted into high vertical wind shear. The JMA followed suit, downgrading Nuri into a depression. The JTWC issued their final warning on Nuri as the storm subsequently made landfall in Yanjiang, China. The JMA followed suit six hours later, issuing their final warning on the system.
The PAGASA issued Tropical Cyclone Signal No. 1 for western Mindanao, southern Luzon, and Visayas on June 11 as Butchoy neared the Philippines. The combination of the system and prevailing southwesterly winds brought showers and thunderstorms across the Philippines. Heavy rainfall in Albay led to the activation of disaster risk management officials and other emergency assets. The rains from the tropical depression prompted PAGASA to declare the start of the rainy season in the Philippines on June 12, 2020, which was also during the country's Independence Day. In Hong Kong, Nuri brought heavy rain. One person also drowned due to rough waters.
Tropical Depression Carina
After about one month of inactivity, on July 11, the JMA designated a low-pressure area near Luzon as a tropical depression. The next day, the JTWC designated the depression as an invest and was given a low chance of developing, and later upgraded to a medium chance. On the following day, the PAGASA upgraded the low-pressure system to a tropical depression and named it Carina.
Carina moved north-northwest over an environment favorable for further development, with low vertical wind shear, established equatorial outflow and 28–29 °C sea surface temperatures. By 12:00 UTC on July 14, Carina rapidly weakened into a low-pressure area, due to an unfavorable environment with strong wind shear. PAGASA then issued their final advisory to Carina, and the remnants dissipated on July 15.
As the low-pressure system was named Carina, PAGASA immediately hoisted Signal #1, the lowest of their storm warning signals, to Batanes, Babuyan Islands and the northeastern portion of Cagayan. Heavy rainfall from Carina caused some damage on Ilocos Norte, Abra and Isabela.
Typhoon Hagupit (Dindo)
On July 31, JMA began monitoring a weak tropical depression that had developed in the Philippine Sea. Later, PAGASA named Dindo to the storm. By the next day, the Joint Typhoon Warning Center designated Dindo as Tropical Depression 03W. With favorable conditions of low vertical wind shear, strong equatorial outflow and 31 °C sea surface temperatures, Dindo intensified into a tropical storm on midday of the same time, and the Japan Meteorological Agency named it as Hagupit. Hagupit then began intensifying in the Philippine Sea, and by August 2, Hagupit was upgraded into a typhoon by the JTWC. The JMA later upgraded Hagupit to a severe tropical storm late on August 2. As Hagupit exited the Philippine Area of Responsibility (PAR), the PAGASA issued its final bulletin on the system. Hagupit was then upgraded into typhoon status by the JMA on August 3, and will later peak in intensity with a pressure of 975 hPa. At around 19:30 UTC, Hagupit made landfall in Wenzhou, China, with winds of 85 mph and pressure of 975 mbar (hPa). After its landfall, Hagupit gradually weakened over China, and by early August 4, the JTWC downgraded the typhoon into a tropical storm. Around midday of the same day, JTWC downgraded Hagupit into a tropical depression and later issued their final advisories on the storm, but the JMA still monitored Hagupit as a tropical storm. The system later would undergo an extratropical transition, a process which got completed on August 6, and the JMA issued their final advisory on the extratropical Hagupit.
In advance of Hagupit, Chinese officials ordered the evacuation of areas vulnerable to flooding. Hagupit caused torrential rainfall over portions of China peaking at 13.11 inches (333 mm) in the Jingshan district of Wenzhou. 15 people were reported dead across South Korea, 6 of them following a landslide in South Chungcheong Province, 11 people were reported missing, and 7 people were injured.
Tropical Storm Sinlaku
On July 29, a tropical disturbance formed and was situated a couple hundred miles east of Manila, Philippines. Struggling to consolidate, the disturbance crossed Luzon with little to no organization and began organizing in the South China Sea. Environmental conditions became conducive for development, and the JMA declared that a tropical depression had formed in the early hours of July 31. Then early on August 1, the depression intensified into Tropical Storm Sinlaku. The storm failed to intensify much afterward, and during the following day, Sinlaku made landfall on northern Vietnam. Shortly thereafter, both agencies issued final advisories on the storm.
Sinlaku produced heavy rain across central and northern Vietnam, resulting in significant flooding. Two people died, one from a collapsed embankment and the other from flash flooding. Thousands of homes were inundated and crops suffered extensive damage. Damage in the nation was about nearly 5.4 billion đồng (US$232,900). Flash floods across Thailand also killed two people.
The remnants of Sinlaku emerged in the Indian Ocean and intensified into a well marked low-pressure area between August 5–8, recreating a lot of torrential rain in portions of India.
Tropical Storm Jangmi (Enteng)
On August 6, the Philippine Atmospheric, Geophysical and Astronomical Services Administration started to monitor a low-pressure area that developed well east of Virac, Catanduanes. On the next day, the Japan Meteorological Agency designated the low-pressure area as a weak tropical depression. Despite a broad and elongated low-level circulation center, it gradually organized, prompting the Joint Typhoon Warning Center to issue a Tropical Cyclone Formation Alert on the depression.