Cyclone Arthur (2007)
Cyclone Arthur (name of RSMCs Nadi: 08F, Identification of JTWCs 09P ) was the eighth tropical Tieffdrucksystem and the fourth tropical cyclone of the South Pacific cyclone season 2006-2007. It was formed on 25 January from a tropical depression and intensified to a strong Category 2 cyclone of the Australian scale, which is used by the Regional Specialized Meteorological Centre in Nadi, Fiji. The Joint Typhoon Warning Center assessed the storm as a Category 1 cyclone light of the Saffir -Simpson Hurricane Scale. Shortly after reaching the peak intensity of the cyclone sch ¨ began to be more alert, since the conditions in the vicinity of the storm center were unfavorable. The storm moved rapidly east- south-easterly direction and the transition to an extratropical cyclone began. After the storm turned to the southeast, the circulation center was completely optional because of strong wind shear. Late on January 26, Arthur could intensify again for a short time, but was on 27 January extratropical. The tropical cyclone had an impact on several smaller islands throughout its existence. Most clearly felt the storm, the people of French Polynesia.
Storm History
On January 21, the Regional Specialized Meteorological Centre in Nadi identified the Tropical Depression 08F, which is about 435 kilometers west-northwest of the island of Savaii formed in Samoa. The depression moved slowly east - southeast over a few days away, the structure of the system and its intensity fluctuated due to the change of day and night as well because of strong wind shear. Around 17:00 clock UTC on 22 January was from the Joint Typhoon Warning Center ( JTWC ) Tropical Cyclone Formation Alert one. The system developed a vast rain band north of the circulation and deep convection formed around the circulation center. The depression moved into an area where the wind shear was weak to moderate. During the day storm warnings for the northeastern quadrant of the system were triggered. The 08F system continued its development when located above the low pressure area formed an anticyclone. A subtropical trough, which was north of the low pressure system, it headed east.
Early on January 24, the system is organized better and increasingly intensified clock at 6:00 UTC to a cyclone. The RSMC Nadi awarded the name Arthur. The cyclone began to rapidly intensify and the structure of the system improved significantly. Around the center is a pronounced deep convection built on, with strong outflow towards the north. A few hours after 08F had intensified to cyclone Arthur, the JTWC issued its first warning on this system, which migrated rapidly in an east - southeasterly direction. The rapid forward movement is due to the influence of a subtropical high pressure ridge to the north and a trough in the south of the system. Later that day began the formation of an eye and the storm intensified to a Category 2 cyclone on the intensity scale of the Australian Bureau of Meteorology. At 18:00 UTC clock this day, the cyclone reached after the evaluation of JTWC his greatest strength with ongoing one-minute wind speeds of 120 km / h, which corresponds to an easier hurricane category 1 of the Saffir -Simpson Hurricane Scale. Early on January 25, the storm reached the criteria of RSMCs in Nadi with ten-minute wind speeds of 110 km / h and a minimum air pressure of 975 hPa his greatest strength. The center was located 635 kilometers north-northwest of Rarotonga at this time. A short time later, the transition began an extratropical cyclone, which quickly lost its organization, since the center of strong wind shear was exposed.
The storm also began to connect with a low- pressure Frontensyystem, which was associated with the remnants of the cyclone Zita. The strong wind shear provided the circulation center partly free, and only in the southeast quadrant of a convection remained. Except for the wind shear, also resulted in the invading dry air to the weakening of the storm. The storm continued to move forward quickly and began a turn to the southeast, along a front. Early on January 26, the JTWC issued its final warning on the system, since it had lost most of its tropical characteristics. Shortly thereafter, there was a new emphasis Arthur and 21:00 UTC clock took the JTWC issuing warnings on again. The brief resurgence of the cyclone was the result of a weakness in the weather front, creating a re-formation of convection to the storm center was possible. Around the same time Arthur left the observation area of the RSMCs in Nadi and arrived in the warning area of the Tropical Cyclone Warning Centre in Wellington. The storm completed the transition to an extratropical area on January 27, so that the final warning was issued to the system.
Preparations and impact
On January 21, a storm warning for Tutuila, American Samoa, Swains Manua and Iceland was granted because the tropical depression approached these islands. The warning came from continuous wind speeds of 55 km / h and gusts up to 75 km / hr. For the Cook Islands, a warning for small vessels was issued because of the high waves could extend that far. These warnings were lifted late on January 23, because the system no longer endangered the islands. On January 24 orange alert has been set for the Austral Islands Rurutu and Tubuai for was later set up the alert level to red at the approach of the storm. Arthur damage in the Cook Islands were low, as the storm between the southern islands of the group and the western part of French Polynesia pass over and consisted mainly of coastal erosion. Heavy rainfall produced in French Polynesia several landslides, causing some homes were damaged in Tahiti and Moorea. The wave height around the islands reached 1.5 to 2 meters. In Tubuai persistent wind speeds of up to 85 km / h were (10 - minütig ) recorded and gusts of up to 115 km / h. Several houses were damaged and blocked several roads on the island by fallen trees. The effects of storm surge on the coast were low.
Designation
When the Tropical Depression 08F incremented to the tropical cyclone and the name Arthur was assigned, it was the third time that this name was used for a storm in the southern Pacific Ocean. Previously the name was used during the South Pacific Zyklosaisons 1981 and 1991. The name was also five times used for storms in the Atlantic Ocean -. 1984, 1990, 1996, 2002, and since the injury in 2007 caused by cyclone Arthur were low in 2008, the name was not removed and remained on the list of names B for the Southern Pacific Ocean.