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Robert Cifelli, Timothy Lang, Steven A. Rutledge, Nick Guy, Edward J. Zipser, Jon Zawislak, and Robert Holzworth

convection associated with MCSs. In this study, we examine the relationship of convection to an AEW as it moved over West Africa, crossed the coastline, and entered the oceanic environment. In particular, we make use of ground-based radar data from three locations—Niamey, Niger; Dakar, Senegal; and Praia, Cape Verde—during the AMMA–NAMMA campaign, representing three distinct geographical locations—continental, coastal, and maritime—to explore the relationship between the wave and MCS precipitation

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Edward K. Vizy and Kerry H. Cook

-level convergence, and cyclonic relative vorticity after 1200 UTC 20 August 2006 can be directly associated with the development and intensification of the second wave, the occurrence of these conditions prior to 1200 UTC suggests that the passage of the first wave is important initially. These results are consistent with those of Lee et al. (1989) and Briegel and Frank (1997) , who note the importance of wind surges prior to tropical cyclogenesis over the northern Indian and western North Pacific Oceans

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Jonathan Zawislak and Edward J. Zipser

, moist air to the south of the jet ( Pytharoulis and Thorncroft 1999 ). Previous studies ( Pytharoulis and Thorncroft 1999 ; Ross and Krishnamurti 2007 ) have concluded that the two circulations are not independent; rather, they exist as a single AEW. Over the ocean, Ross and Krishnamurti (2007) (for 850-hPa vorticity maxima) also conclude that one must distinguish between the convergence of the vorticity tracks and the merging of vorticity centers; convergence could lead to two weak waves, while

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Wei Zhong, Da-Lin Zhang, and Han-Cheng Lu

symmetrization rate of an intense geophysical vortex. Dyn. Atmos. Oceans , 37 , 55 – 87 . Schecter , D. A. , and M. T. Montgomery , 2004 : Damping and pumping of a vortex Rossby wave in a monotonic cyclone: Critical layer stirring versus inertia-buoyancy wave emission. Phys. Fluids , 16 , 1334 – 1348 . Schecter , D. A. , and M. T. Montgomery , 2007 : Waves in a cloudy vortex. J. Atmos. Sci. , 64 , 314 – 337 . Schubert , W. H. , M. T. Montgomery , R. K. Taft , T. A. Guinn

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Zhuo Wang, M. T. Montgomery, and T. J. Dunkerton

easterly wave pouch creates conditions favorable for amplification of curvature vorticity (in the comoving frame) and upward extension of the ITCZ convergence from the boundary layer to the interior. Another role of the oceanic ITCZ is to promote large-scale hydrodynamic instability, resulting in the excitation of slower easterly waves and amplification of “teardrop” cyclonic gyres ( Hack et al. 1989 ; Wang and Magnusdottir 2005 ). Simultaneous development of multiple gyres is possible via this

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Zhuo Wang, M. T. Montgomery, and T. J. Dunkerton

the cyclonic circulation. As articulated in DMW09 , positive feedbacks exist when low-level vorticity and deep moist convection are present simultaneously in the pouch; it is the cooperation of these feedbacks that provides an efficient pathway to storm development, especially in oceanic basins that are otherwise marginal or hostile to development. We say that the precursor or “parent” wave is diabatically activated when deep moist convection persists within the pouch, a likely sign of its

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Oreste Reale, William K. Lau, Kyu-Myong Kim, and Eugenia Brin

SOP-3 covering the period from 15 August to 15 September 2006. From Fig. 1 (left panel), the two strongest waves of the period, which are the subject of this study, can be seen: 1) the wave located at about 5°W on 23 August, undergoing transition from a continental to an oceanic environment on the following day, and appearing at about 20°W on 26 August (W1); and 2) the wave located at about 15°–40°W on 12–15 September (W2). The former is a nondeveloping wave, to be discussed in section 3b , the

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Wallace Hogsett and Da-Lin Zhang

1. Introduction Tropical cyclones (TCs) devastate life and property by concentrating large amounts of kinetic energy (KE) within a small radius in the inner-core regions. Most of the KE is generated through a continuous series of energy conversions, with the latent energy (LE) as the fundamental source, which is obtained primarily through upward fluxes of latent heat from the underlying warm ocean and released in convective clouds in the eyewall. Some of the released LE is used to increase KE

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Joël Arnault and Frank Roux

, 334 – 342 . Paradis , D. , J-P. Lafore , and J-L. Redelsberger , 1995 : African easterly waves and convection. Part I: Linear simulations. J. Atmos. Sci. , 52 , 1657 – 1679 . Payne , S. W. , and M. M. McGarry , 1977 : The relationship of satellite inferred convective activity to easterly waves over West Africa and the adjacent ocean during phase III of GATE. Mon. Wea. Rev. , 105 , 413 – 420 . Pinty , J. P. , and P. Jabouille , 1998 : A mixed-phase cloud

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Stephen R. Guimond, Gerald M. Heymsfield, and F. Joseph Turk

conducted the Tropical Cloud Systems and Processes (TCSP) field experiment in the Caribbean, Gulf of Mexico, and eastern Pacific Ocean basins with the purpose of discovering new insights into the life cycle of TCs ( Halverson et al. 2007 ). Hurricane Dennis tracked through this region in early July, forming from a tropical wave in the eastern Caribbean and growing to a category-4 hurricane before weakening over Cuba. Dennis then emerged into the Gulf of Mexico at 0900 UTC 9 July as a category-1 storm

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