Hurricane Genevieve, also known as Typhoon Genevieve, was a strong and long-lived tropical cyclone that became the fourth-strongest tropical cyclone of the 2014 Pacific typhoon season. It was also the first tropical cyclone to exist in all the three North Pacific tropical cyclone basins since Dora in 1999. Genevieve formed from a tropical wave well to the south-east of Hawaii on July 25, but weakened quickly into a remnant low due to high wind shear on July 28. The system briefly reformed in July to the south of Hawaii before dissipating once again on July 31.
Several days later, on August 2, Genevieve regenerated. Owing to better conditions for intensification, Genevieve began to rapidly intensify, reaching hurricane strength on August 6 and major hurricane strength on August 7 shortly before crossing the International Date Line into the Western Pacific basin, where Genevieve was reclassified as a typhoon by the Japan Meteorological Agency (JMA).
After reaching peak intensity as a Category 5 typhoon on August 7 and 8 to the west-southwest, Genevieve began to weaken as conditions worsened. The storm rapidly weakened to severe tropical storm strength on August 10. On August 12, the JMA downgraded Genevieve to a tropical depression, and Genevieve dissipated on August 14.
Meteorological history
Origin and regeneration
The National Hurricane Center (NHC) began to track a tropical wave associated with a few showers and thunderstorms, moving westward off the coast of northern Central America on July 17. Four days later, thunderstorm activity became stronger; by July 22, the area of low pressure became better organized. On July 23, the NHC noted that the system could become a tropical depression within the next two days; however, they also noted that wind shear could increase within a couple of days. After an ASCAT pass and an increase in convection, the NHC upgraded the storm to Tropical Storm Genevieve on July 25. A few hours later, the system attained its initial peak strength of 45 mph (75 km/h).
Shortly afterwards, increased wind shear took its toll on the system, causing Genevieve to lose its organization as it continued westward, under the influence of a subtropical ridge and the Intertropical Convergence Zone. After the low-level circulation center was exposed and became separated from the deep convection, the NHC downgraded Genevieve to a tropical depression on July 26. Although deep convection increased near the center early on the next day, Genevieve continued to fight westerly shear when crossing 140°W, moving into the waters monitored by the Central Pacific Hurricane Center (CPHC). Due to the lack of deep convection, the CPHC indicated that Genevieve had become a post-tropical remnant low early on July 28, as only a low-level cloud swirl remained. However, the CPHC noted the possibility of re-development since shear was forecast to decrease.
Roughly 36 hours later, the remnants of Genevieve regenerated into a tropical depression to the southeast of the main Hawaiian Islands. The system briefly became better organized on July 30, prompting the CPHC to forecast the storm would re-intensify into a tropical storm. However, by the end of the day, the low-level circulation center had become displaced to the east of the deep convection due to increased southeasterly shear and infiltration of dry air. By 21:00 UTC July 31, the CPHC reported that Genevieve had once again weakened into a remnant low, as only an isolated area of deep convection remained west of the center.
Intensification and peak intensity
The remnants of Genevieve continued to travel in a generally westward direction, moving into an environment more conducive for tropical development, and on the afternoon of August 2, Genevieve regenerated into a tropical depression, as the storm reacquired deep convection and its outflow improved. By 21:00 UTC the same day, Genevieve reacquired tropical storm intensity, continuing to travel westward around the subtropical ridge to its north, but only six hours later, the CPHC downgraded Genevieve into a tropical depression. Deep convection near the center increased and decreased several times, but Genevieve failed to re-intensify. After moving south-southwest, Genevieve turned west-northwest on August 4 as it continued to track around the ridge to its north.