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Typhoon Chan-hom, known in the Philippines as Typhoon Emong, is the sixth tropical depression and the second tropical storm to develop during the 2009 Pacific typhoon season. Chan-hom developed out of an area of convectional cloudiness associated with an area of disturbed weather which originated from the remnants of Tropical Depression Crising and formed southeast of Nha Trang, Vietnam on May 2. Moving towards the northeast, it slowly organized according to JTWC who issued a TCFA, and JMA classified Chan-hom as a minor tropical depression later that day. The next day, both JTWC and JMA upgraded the depression to a tropical storm and named it Chan-hom. On May 6, the storm intensified into a Category 1 typhoon, and on May 7, Chan-hom intensified into a Category 2 typhoon equivalent. However, Chan-hom weakened into a severe tropical storm after passing northern Luzon. On May 14, Chan-hom regenerated into a Tropical Depression, and dissipated late on May 15. Laos submitted the name, which means a kind of tree. ==Meteorological history== Typhoon Chan-hom was first identified as a disorganized area of low pressure on May 2, 2009 situated roughly southeast of Nha Trang, Vietnam in the South China Sea. Deep convection was mainly confined to the northern portion of the system; however, a band of cloud cover had begun to wrap around the center of circulation during the afternoon. Later that day, the Japan Meteorological Agency (JMA) began monitoring the developing low as a tropical depression. Hours later, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert for the system as convection consolidated around the center of circulation. Further development was anticipated as the storm slowly moved through an area of warm sea surface temperatures and low wind shear, conditions favoring tropical cyclone formation. Early on May 3, the JTWC classified the system as Tropical Depression 02W. Following the formation of a central dense overcast, both the JTWC and JMA upgraded the depression to a tropical storm, at which time it received the name Chan-hom.〔〔 Situated to the north of a weak subtropical ridge, little movement was expected over the next two days.〔 Modest strengthening took place as Chan-hom drifted slowly towards the north before taking a more northeasterly path.〔〔 By the morning of May 5, the storm developed a symmetrical cloud cover with notable banding features.〔 According to the JMA, maximum sustained winds within the cyclone had reached 95 km/h (60 mph), prompting the agency to upgrade Chan-hom to a severe tropical storm.〔 On May 6, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) began issuing advisories on Chan-hom as it moved into their area of responsibility and assigned it the local Philippine name Emong. Within hours of PAGASA's first advisory, the JTWC assessed Chan-hom to have attained winds of 120 km/h (75 km/h), equivalent to a Category 1 hurricane on the Saffir–Simpson Hurricane Scale.〔 The JMA followed suit six hours later, classifying the system as a minimal typhoon.〔 Further intensification took place as the typhoon's outflow improved in response to a mid-latitude trough over central China.〔 Several hours before making landfall along the western coast of Luzon on May 7, an eye-feature began to develop. Satellite imagery depicted a depression in the cloud cover over the center of circulation as well as a broken ring of deep convection.〔 In light of this information, the JTWC assessed Chan-hom to have reached its peak intensity at this time, packing sustained winds of 160 km/h (105 mph) and an estimated barometric pressure of 956 mbar (hPa; 28.23 inHg).〔 However, the JMA stated that the typhoon was slightly weaker, having maximum winds of 120 km/h (75 km/h) and a pressure of 975 mbar (hPa; 28.79 inHg).〔 Just prior to crossing the coastline, the storm began to weaken as wind shear increased. Within hours of moving over the mountainous terrain of northern Luzon, the cyclone quickly diminished. The low-level circulation became detached from convection and pressure readings over land indicated a minimum pressure around 1004 mbar (hPa; 29.65 inHg). Although wind shear remained at unfavorably high levels,〔 Chan-hom maintained tropical storm intensity through its crossing of Luzon through the end of May 8.〔〔 By May 9, all that remained of Chan-hom was an exposed low-level circulation with convection displaced over to the east. With the addition of dry air entering the system, the storm was not expected to regain strength as it began to take a northward turn.〔 Around this time, PAGASA issued their final advisory on the system as they assessed it to have degenerated into a non-convective remnant low pressure system. The JTWC issued their initial final advisory on Chan-hom during that morning;〔 however, later analysis determined that the system remained a tropical depression until the morning of May 11.〔 The JMA and JTWC continued to monitor the remnants of Chan-hom through May 13, at which time it dissolved to the southeast of Okinawa, Japan.〔〔 However, the remnant low of Chan-hom briefly regenerated into a tropical depression on May 14, before finally dissipating on the next day. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Typhoon Chan-hom (2009)」の詳細全文を読む スポンサード リンク
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