|
Hurricane Iselle was the strongest tropical cyclone to make landfall on the Big Island of Hawaii in recorded history. The eleventh named storm of the annual hurricane season, Iselle developed from an area of disturbed weather southwest of Mexico on July 31, 2014. Assuming a west-northwest course that it would maintain throughout its existence, generally favorable atmospheric conditions allowed for gradual strengthening, with the cyclone attaining hurricane status a day after formation. Continued strengthening progressed for several days up until August 4, when Iselle reached peak intensity with maximum sustained winds of 140 mph (220 km/h) and a minimum barometric pressure of 947 mbar (hPa; 27.96 inHg), making it a Category 4 hurricane. Thereafter, Iselle encountered hostile environmental conditions and quickly weakened before making landfall on the Big Island on August 7 as a moderate tropical storm. Its passage over the island disrupted the cyclone, and Iselle later dissipated on August 9. Widespread precautionary measures took place across Hawaii as forecasts indicated the potential for a Hawaiian landfall as early as August 2. Then-governor Neil Abercrombie signed an emergency proclamation into effect, and numerous government facilities were closed. Several airlines cancelled flights servicing the archipelago. Upon making landfall, Iselle brought torrential rainfall and caused strong winds which resulted in widespread power outages and downed trees. The storm caused heavy crop damage, estimated at $66 million (2014 USD), including 60% of the state's papaya that was lost. This was enough to be classified as an agriculture disaster, and was eventually declared a disaster by Federal Emergency Management Agency after initially being denied. In the end, Iselle caused a total of $79.2 million (2014 USD) in damages, and killed one person on Kauai as a result of flooding. ==Meteorological history== In late July 2014, computer models began to indicate the possible formation of a low-pressure area off the coast of southwestern Mexico, prompting the National Hurricane Center (NHC) to assess the region with a low probability of tropical cyclogenesis on July 24. These forecasts began to come to fruition on July 28 when an area of thunderstorms associated with a tropical wave developed off the Mexican coast. Tracking westward in favorable conditions, the system organized over the following days. At 21:00 UTC on July 31, the NHC classified the disturbance as Tropical Storm Iselle due to the system's organization and the detection of tropical storm-force winds by the MetOp-B scatterometer. At the time, Iselle was located roughly 1,075 mi (1,730) km southwest of the southern tip of the Baja California peninsula. Steady intensification continued after formation, with the NHC indicating the possibility of rapid intensification. on August 1, Iselle began to develop an eye, and this progressive pattern of organization prompted the NHC to upgrade the storm to hurricane status at 03:00 UTC the following day. Although favorable conditions allowed for the uninhibited growth of Iselle early in its development, moderate wind shear briefly impacted the hurricane on August 2, preventing thunderstorms from intensifying and causing the storm to become slightly malformed vertically. However, these conditions abated shortly afterwards, allowing Iselle to resume strengthening and reach Category 2 hurricane status late that same day. With wind shear no longer impinging on the organization of Iselle, the tropical cyclone gradually became more symmetric, allowing for the hurricane's once ragged eye to clear itself of cloud cover and the storm to intensify to major hurricane status on August 3. Despite the attainment of some annular tropical cyclone characteristics, Iselle briefly weakened below major hurricane status before rapidly reaching Category 4 strength at 15:00 UTC on August 4. Consequently, Iselle reached peak intensity with maximum sustained winds of 140 mph (220 km/h) and a minimum barometric pressure of 947 mbar (hPa; 27.96 inHg). At the same time, the hurricane exhibited an eye 30 mi (45 km) across.〔 Following peak intensity, the combination of increasing wind shear and lowering sea surface temperatures began to slowly weaken Iselle, bringing it below Category 4 intensity early on August 5. At 15:00 UTC that day, forecasting responsibility transferred from the NHC to the Central Pacific Hurricane Center (CPHC). Continued wind shear caused the storm to further degrade and its eye to become ragged in appearance. The CPHC downgraded Iselle below major hurricane intensity six hours after the hurricane had moved into the agency's area of responsibility. Although wind shear began to decrease thereafter, abundant dry air caused Iselle to rapidly weaken, dropping to Category 1 intensity on August 6. However, the suppressed wind shear allowed for the hurricane to reorganize and maintain a large eye as it tracked towards Hawaii. Only slow degradation of Iselle's structure followed, though on August 7, the storm's eye had faded and the CPHC estimated that Iselle had weakened to a minimal hurricane. Becoming increasingly disorganized, Iselle weakened to a tropical storm the next day before making landfall at 12:30 UTC along the eastern coast of Hawaii island. The mountainous terrain of the island largely disrupted the main cyclonic circulation of Iselle, which manifested as a collection of small vorticies south of the Hawaiian islands. Due to the loss of any sustained thunderstorm activity at the storm's center, the CPHC decided to downgrade Iselle to a remnant area of low pressure on August 9; at the time, the disturbance was centered roughly 200 mi (320 km) west-southwest of Honolulu. 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「Hurricane Iselle (2014)」の詳細全文を読む スポンサード リンク
|