2005 Pacific typhoon season

The 2005 Pacific typhoon season was the least active typhoon season since 2000, producing 23 named storms, of which 13 became typhoons (including 3 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 2005, though most tropical cyclones typically develop between May and November. The season's first named storm, Kulap, developed on January 13, while the season's last named storm, Bolaven, dissipated on November 20. The season's first typhoon, Haitang, reached typhoon status on July 13, and became the first super typhoon of the year three days later.

The scope of this article is limited to the Pacific Ocean, to the north of the equator between 100°E and the 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, one from the JMA and one from PAGASA. The Japan Meteorological Agency (JMA) will name a tropical cyclone should it be judged to have 10-minute sustained wind speeds of at least anywhere in the basin, while 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 TSR forecastsDate Tropicalstorms TotalTyphoons IntenseTCs ACE Ref Average (1965–2004) 26.8 16.9 8.6 305 March 14, 2005 25.9 16.1 9.8 340 May 5, 2005 27.6 17.5 8.9 314 June 7, 2005 27.6 17.5 9.4 328 July 7, 2005 27.6 17.5 9.5 333 August 5, 2005 27.6 17.5 9.4 328 Other forecastsDate ForecastCenter Period Systems April 27, 2005 GCACIC January–December 25 tropical cyclones June 24, 2005 GCACIC January–December 24 tropical cyclones 2005 season ForecastCenter Tropicalcyclones Tropicalstorms Typhoons Ref Actual activity: JMA 33 23 13 Actual activity: JTWC 25 24 18 Actual activity: PAGASA 17 14 12

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 included the Tropical Storm Risk (TSR) Consortium of University College London, PAGASA and Taiwan's Central Weather Bureau. Some of the forecasts took into consideration what happened in previous seasons and the La Niña conditions that were observed during the previous year.

On March 14, TSR published their extended range forecast for the 2005 season, in which the anticipated that they would see tropical activity slightly below the average. They predicted that there would be a total of 25-26 tropical storms and 16 typhoons. The TSR, however, forecast that their number of intense typhoons would go slightly above the average, bringing their prediction of 10 intense typhoons. Their main reasons behind this is due to weaker trade force winds occurring in many parts of the basin, and there would be an enhanced cyclonic vorticity over the northwestern part of the Pacific. On April 27, the GCACIC made their first forecast for the season, expecting about 24 tropical storms developing, in which 15 of them would strengthen into typhoons. By May 5, TSR published their first forecast, still predicting a near average typhoon season. Around this time, 27-28 tropical storms, 17-18 typhoons and 9 intense typhoons were predicted, with the slight increase of the number of tropical storms were due to a slight increase in temperatures within the Niño 3.75 region.

TSR's second forecast was released on June 7, now predicting a slightly above average season, with the only change for their predicted cyclone numbers was a slight increase of intense typhoons to 9.4. The GCACIC made their second and final forecast for the season on June 24, slightly increasing their numbers to 25 tropical storms and 16 typhoons. The TSR maintained their predictions after their third forecast update on July 5. Sea-surface temperatures within the Pacific were predicted to be more warmer than that predicted back in the May forecast. On August 5, TSR released their fourth and final forecast for the season, still remaining the same numbers along with the same reasonings.

Seasonal summary

The Accumulated Cyclone Energy (ACE) index for the 2005 Pacific typhoon season as calculated by Colorado State University using data from the Joint Typhoon Warning Center was 309.9 units.

The 2005 season was a near-average season, the number of typhoons in the year was twenty-three, much less than the average of twenty-seven. The number of typhoons that made landfall in Japan was three, which is almost the average (2.6). In general, this is not a year in which the impact of typhoons has been especially notable. The number of typhoons that passed near Okinawa was eight, which is slightly larger than the average of seven, and this is because this year there are some typhoons moving through the Sakishima Islands towards the Taiwan or China. This year's major typhoons are reviewed below.

Although the season was quiet, some typhoons caused extensive damages in many places, especially in China where eight typhoons struck the country. First, Typhoon Haitang became the strongest storm in the basin this year and caused about $1.1 billion in damages in Taiwan and China in mid July. In August, Typhoon Matsa made landfall in Eastern China and caused about $2.23 billion in damages. Later that same month, two powerful typhoons made landfall, causing extreme damage and some casualties. Similar to Haitang, Typhoon Longwang made landfall in Taiwan and China at a strong intensity causing damages.

Systems Severe Tropical Storm Kulap

On January 12, a tropical disturbance developed within an area of light vertical wind shear. This allowed deep convection to develop over a broad low-level circulation. The next day, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert (TCFA) as the system continued to develop. Later that day, they issued their first advisory on Tropical Depression 01W while the storm was located about southwest of Chuuk. Several hours later, the Japan Meteorological Agency (JMA) also designated the system as a tropical depression. Early on January 15, the JTWC upgraded 01W to a tropical storm as the system turned towards the north. The northward movement was the result of the system traveling along the edge of a low to mid-level ridge located to the east. About 12 hours later, the JMA upgraded the depression to a tropical storm and gave it the name Kulap; which was contributed by Thailand and is the Thai word for rose. Kulap gradually intensified over the next two days, reaching its peak intensity with winds of 10-minute winds) around 1800 UTC on January 17, making it a severe tropical storm according to the JMA. However, at the same time the JMA assessed Kulap to have reached its peak intensity, the JTWC classified it as a minimal typhoon with winds of 1-minute winds). Shortly after reaching its peak intensity, the storm began to undergo an extratropical transition and weaken. Late on January 18, the JTWC issued their final advisory on Kulap despite the storm remaining tropical. The JMA considered Kulap to have been a tropical storm until early the next day. The storm dissipated as a weak extratropical system around 1200 UTC on January 19. Between January 13 and 14, the storm produced heavy rains over the island of Chuuk. Upwards of of rain fell during the two-day span, of which fell in 24 hours.

Severe Tropical Storm Roke (Auring)

A tropical disturbance formed on March 11, near the equator. It rapidly developed into Tropical Depression 02W on March 13 as it steadily moved north, then west towards the Philippines. Later that day, it entered warm waters as it was upgraded into Tropical Storm Roke. Due to a strong ridge of high pressure north of it, it moved west-southwest, attaining peak intensity as a severe tropical storm. Roke then entered the PAR, giving the name Auring later that day. It made landfall in eastern Visayas on March 16. The next day, Roke rapidly weakened due to cool waters and dissipated on March 18. Roke is a male Chamorro name. Seven people were killed and damages amounted to $166,000 (2005 USD).

Typhoon Sonca (Bising)

A large area of convection formed on April 11. Late on April 14, a newly disorganized disturbance formed in that area and steadily intensified. The next two days, the disturbance interacted with another low-pressure area as it moved north towards warm waters. On April 17, the depression weakened due to strong vertical windshear. The JTWC designated as Tropical Depression 03W on April 18. Although the JMA started classifying it as a tropical depression on April 21. It rapidly intensified into a tropical storm, with the JMA naming it Sonca late on April 20. Very early on April 21, the PAGASA classified it as a storm, naming it Bising. Convection built up the storm again on April 22 and entered an area with favorable conditions. The next day, Sonca rapidly intensified into a Category 4 typhoon until it reached peak intensity on mid-April 24. Sonca rapidly weakened due to cool waters and dissipated on April 27.

Tropical Depression Crising

On May 8, a parade of tropical disturbances formed and affected southern Philippines from an ITCZ. As the ITCZ weakened on May 13, the last disturbance formed southeast of Mindanao, Philippines. It moved north until it became a tropical depression on May 16 at 0000 UTC (0800 PHT) east of Surigao on Mindanao Island. It was assigned the name Crising by PAGASA. The storm never organized into a tropical storm and did not receive the more recognized International name for West Pacific storms. The storm drifted northwest then southwest and began losing convection. PAGASA stopped tracking the storm 24 hours later on the 17th at 0000 UTC (0800 PHT) east of Surigao.

Typhoon Nesat (Dante)

A tropical depression formed from a tropical wave late on May 28. It rapidly intensified into Tropical Storm Nesat on May 30, rapidly moving west. This was a powerful storm that formed on May 30 about south-southeast of Guam as Tropical Depression 04W. It was quickly upgraded to Tropical Storm Nesat overnight at 1800 UTC (0200 PHT May 31). Nesat is a Cambodian word for fisherman. On the evening of June 1, it strengthened into Typhoon Nesat. On June 2, it entered the Philippine area of responsibility and was assigned the name Dante for Philippine warnings. Typhoon Nesat (Dante) quickly grew to a Category 4 storm as it approached the Philippines, but it curved away to the northeast and did not pose a threat to land. Waxing and waning in strength it eventually became extratropical southeast of Honshū, Japan at tropical storm strength on the morning of June 10 at 0000 UTC (0900 JST).

Tropical Depression Emong

A large tropical disturbance formed on July 2. The PAGASA issued a tropical depression strength near the Philippines on July 4 at 0600 UTC (1400 PHT) about northeast of Catarman on Samar Island, giving the name Emong. It was assigned the name Emong by PAGASA. The storm never organized into a tropical storm and did not receive the more recognized International name for West Pacific storms. As a poorly organized depression it drifted over Luzon on July 5. Upper-level shear and the depression's landfall caused the storm to lose organization on July 6 while located about south of Hong Kong.

Typhoon Haitang (Feria)

There were 15 deaths in Taiwan and another 14 in mainland China.

Tropical Storm Nalgae