The 2010 Pacific typhoon season, with 14 named storms, was the least active Pacific typhoon season on record. Seven of them strengthened into typhoons while one reached super typhoon intensity. All of the 14 named storms developed west of 150°E.
The season ran throughout 2010, though most tropical cyclones tend to develop between June and October. The season's first named storm, Omais, developed on March 24 while the season's last named storm, Chaba dissipated or became extratropical on October 30. During the season only three storms were notable. Typhoon Kompasu was the strongest storm to make landfall over in South Korea in 15 years. In September, Typhoon Fanapi struck Taiwan and China, causing heavy damage in the two countries. No storms made landfall in mainland Japan, only the second such occurrence since 1988. During October, Typhoon Megi reached its peak intensity with a minimum barometric pressure of 885 hPa, making it one of the most intense typhoons ever recorded. In addition, a rare subtropical storm had developed during December and intensified into Tropical Storm Omeka where it crossed the basin.
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 km/h (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
Each season 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.
City University of Hong Kong
Since the 2000 Pacific typhoon season, the Guy Carpenter Asia-Pacific Climate Impact Centre (GCACIC), of the City University of Hong Kong (CityUHK), have issued forecasts of activity for each upcoming typhoon season. Forecasts on the number of tropical cyclones, tropical storms and typhoons there would be during 2010 in the Western Pacific were released in April and June. For the first time this year the GCACIC issued forecasts in May and July, which predicted how many tropical cyclones would make landfall in South China, and pass within 100 km (62 mi) of either the Korean Peninsula or Japan during 2010.
In its April 2010 forecast; GCACIC predicted that 28 tropical cyclones, 24 tropical storms, and 16 typhoons would form in the western north Pacific this year. However, in its June forecast the GCACIC reported that they now only expected 27 tropical cyclones, 23 tropical storms, and 15 typhoons, to form during the season. As a result of their predictions the GCACIC also predicted that tropical cyclone activity would be below average for the twelfth year in a row. In May the GCACIC forecasted that between May and December, six tropical cyclones would make landfall on Southern China and another six tropical cyclones would make landfall on or pass within 100 km (62 mi) of either the Korean Peninsula or Japan. In July the GCACIC forecast that between July and December three tropical cyclones would make landfall on Southern China, while four tropical cyclones would make landfall on or pass within 100 km (62 mi) of either the Korean Peninsula or Japan.
Tropical Storm Risk Consortium
Since the 2000 Pacific typhoon season, the Tropical Storm Risk Consortium (TSR) of the University College of London have issued forecasts of activity for each upcoming typhoon season. Forecasts on the number of tropical storms, typhoons and intense typhoons there would be during 2010 in the Western Pacific were released in March, May, July and August. In its March forecast TSR predicted that the season would see activity close to the average with 26 tropical storms, 16 typhoons and seven intense typhoons developing during the season. In its May forecast, while lowering their initial prediction for the amount of tropical storms and typhoons, TSR continued to predict that the season would see activity close to the average, with 24 tropical storms, 15 typhoons and nine intense typhoons developing during the season. In its July forecast TSR significantly lowered their forecast and reported that they now expected activity to be 20% below average, with 23 tropical storms 14 typhoons and seven intense typhoons developing during the season. In its August forecast TSR predicted that activity would be 25% – 30% below average with 23 tropical storms, 13 typhoons and six intense typhoons developing during the season. TSR also predicted that if their August forecast came true then the season would be in the lowest 25% of seasons.
National meteorological service predictions
The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported on January 7 that they were expecting a total of 19 tropical cyclones to pass through the Philippine area of responsibility during 2010. On March 23 the Hong Kong Observatory (HKO), predicted that less than six tropical cyclones would affect Hong Kong during the season. As a result of being under the influence of a weakening El Niño, the HKO also predicted that the chances of a tropical cyclone affecting Hong Kong before June was not high. After Vietnam was hit by Tropical Depression 01W in January, the Vietnamese National Center for Hydro Meteorological forecasts predicted in May that 6–7 tropical cyclones would affect Vietnam during 2010. While the Thai Meteorological Department predicted that one or two tropical cyclones would affect Thailand between August and November. On June 30, the Central Weather Bureau of Taiwan predicted that the 2010 season would be below its normal climatic average of 26.6, and predicted that 20–23 tropical storms, would occur over the Western Pacific during 2010. The Central Weather Bureau also predicted that between two and four tropical storms would affect Taiwan during 2010. After the slow start to the season, on July 5, PAGASA reported that they now only expected 13–15 tropical cyclones to pass through the region.
Season summary
The first tropical cyclone of the season; Tropical Depression 01W formed on January 18, about 300 km to the northeast of Brunei. During the next 2 days the depression moved quickly and made landfall on Vietnam and dissipated over Cambodia during January 20. The depression caused 3 deaths and caused US$243,000 in damage to Vietnam. After 01W had dissipated the Western Pacific became dormant until Tropical Storm Omais formed about 325 km (202 mi) to the southeast of Chuuk Island on March 22. During the next couple of days Omais impacted the Micronesian islands of Woleai, Fais Ulithi and Yap, before moving into the Philippine area of responsibility and being named as Agaton by PAGASA. However, Omais (Agaton) dissipated on March 26 before it could affect the Philippines. After Omais dissipated there were 2 non-developing tropical depressions only monitored by the JMA in April and June before on July 11 the first typhoon of the season: Conson formed. Conson quickly intensified becoming a typhoon the next day, before making landfall on the Philippines during July 13.
Overall, there were 14 named tropical storms during the season, which was the lowest on record; this was 2 less than the previous record set in 1998, and 12.7 less than the average of 26.7 storms. Although activity was below normal throughout the year, the quietest time of the year, with respect to climatology, was from October to December. Only two storms formed during the time period, which was 5.7 less than average. The overall inactivity was due to a variety of meteorological conditions, including decreased vorticity and suppressed convection. During the summer of 2010, convective activity in southeastern Asia was shifted to the northern Indian Ocean due to winds in the upper atmosphere. However, sea surface temperatures were above normal due to an ongoing La Niña, despite that typically being a favorable factor in tropical cyclogenesis.
Systems
Tropical Depression 01W
On January 16, a disorganized area of low pressure formed in the south China Sea. The next day, it gradually intensified into a weak tropical disturbance by the JTWC. Early on January 18 the JMA reported that it was upgraded to a tropical depression which had formed within the northeast monsoon about 320 km (200 mi) to the north-west of Bandar Seri Begawan in Brunei. The depression's low level circulation center was partially exposed and located within an area of moderate to strong vertical wind shear. However over the next 12 hours, whilst the depression moved towards Vietnam, the low level circulation center rapidly consolidated and became well defined after the vertical wind shear around the system relaxed. As a result of this the JTWC initiated advisories on the depression, designating it as Tropical Depression 01W. During the next day, the depression weakened with the low level circulation center becoming partially exposed, as it moved over an area of cold sea surface temperatures. As a result of this the JTWC issued their final advisory on the system later that day. The depression then made landfall on Vietnam near Gò Công early on January 20 before the JMA then issued their final advisory later that day as the system dissipated over Cambodia.
Within Vietnam strong waves caused by the tropical depression, causing three people to die, while rowing their coracles to find shelter.
Tropical Storm Omais (Agaton)
On March 18, the JTWC reported that an area of deep atmospheric convection had persisted about 325 km (202 mi) to the southeast of Chuuk Island in southern Micronesia. At this stage the poorly organised deep convection was located over a low level circulation center and was in an area of low wind shear. Over the next couple of days both the low level circulation center and the deep convection gradually became better organized, prompting the issuance of a Tropical Cyclone Formation Alert late on March 20. During the next day convection continued to build over the low level circulation center, which became well defined whilst moving around the subtropical ridge. The JTWC then initiated advisories on the system later that day, designating it as Tropical Depression 02W, although the JMA did not designate the system as a tropical depression until early on March 22. During March 22 further development of the system was hampered by an anticyclone to the east of the system that caused moderate to strong wind shear. Early of the next day, JTWC upgraded the depression into a tropical storm, and on 24 March JMA upgraded it to Tropical Storm Omais, the first of the season. Late on March 25, the JTWC downgraded Omais to tropical depression strength. Tropical Depression Omais re-gained tropical storm status late on March 26 as it was becoming extratropical.
Typhoon Conson (Basyang)
Typhoon Conson, developed into a tropical depression early on July 11 before rapidly developing into the second tropical storm of the season and named as Conson during the next day. During that afternoon Conson, kept intensifying before the JMA reported that Conson had reached its initial ten-minute peak sustained wind speeds of 110 km/h (70 mph), which made it a severe tropical Storm on the JMA's scale. Later that day, the JTWC reported that Conson had intensified into a typhoon before reporting early on July 13 the next day that it had reached its initial one-minute peak sustained wind speeds of 110 km/h (70 mph) which made it a Category 1 typhoon on the Saffir–Simpson hurricane scale. During July 13, Conson started to weaken as it interacted with the Philippines before it made landfall near General Nakar, Quezon. Whilst over the Philippines Conson moved towards the west and passed over Manila before moving into the South China Sea early on July 14. During that day Conson weakened further under the influence of high vertical wind shear before during the next day the vertical wind shear weakened slightly. As a result, Conson intensified over the South China Sea and became a typhoon early on July 16, with the JMA reporting ten-minute peak sustained wind speeds of 130 km/h (80 mph), whilst the JTWC reported peak one minute wind speeds of 150 km/h (95 mph) later that day as it passed closed to Hainan Island. After passing close to Hainan island, Conson moved into an area with high levels of vertical wind shear and as a result it rapidly weakened into a tropical storm, before making landfall in Vietnam during July 17. On July 18 Conson dissipated.
On the morning of July 13, DEPED suspended all elementary and preschool classes in Metro Manila and some other provinces. All flights were canceled due to heavy rains and strong winds brought by Conson. Severe flooding was also reported in Bicol Region.
In addition, Conson sank three fishing vessels in the province of Catanduanes, Philippines. JTWC's 6:00 bulletin indicated that Conson would be passing through Metro Manila at about 2 or 3 in the morning the following day, which it did.