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Cheng-Ku Yu and Ying-Hsun Hsieh

and Bresch 1991 ; Sun and Chern 1993 ; Leu and Lin 2004 ; Chien and Lin 2004 ; Huang 2007 ). The convective lines occurring offshore in this particular geographical location are one of the most well-known and frequent mesoscale phenomena in Taiwan ( Yu and Lin 2008 , hereafter YL08 ). Documentation of these lines can provide an excellent opportunity to improve our general understanding of physical processes leading to the formation of moist convection off a mountainous island coast. With

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Matthew D. Parker

relatively little study to this point in time. Part I combined a case study and idealized numerical simulations as an introductory exposition of the basic structures of such PS systems. In Part I , convective lines with PS precipitation were found to develop in environments with a combination of deep line-parallel wind shear and low-level line-perpendicular wind shear. In such situations, lower-tropospheric storm-relative hydrometeor advection and outflow expansion toward the line’s right 1 produces

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Cheng-Ku Yu and Che-Yu Lin

shore ( Fig. 1 ). Such a geographical configuration represents an excellent natural laboratory to explore our knowledge of coastal convection influenced by both land–sea thermal contrasts and topographic effects. In this particular geographical location, the cloud and/or precipitation lines occurring off the eastern coast of Taiwan are one of the most well-known and frequent mesoscale phenomena. These offshore lines are typically oriented parallel to the coast. They are frequently characterized by

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Matthew D. Parker

) . Along these lines, much of the discussion about evolutionary modes of linear convective systems has centered upon the relative strength of the line-perpendicular vertical wind shear (extending back through seminal papers by Thorpe et al. 1982 ; Rotunno et al. 1988 ). However, comparatively few studies have considered the possible impacts of along-line wind shear. It is perhaps for this reason that PS MCSs appear to have received little, if any, detailed attention as a kinematically and dynamically

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Linlin Zheng, Jianhua Sun, Xiaoling Zhang, and Changhai Liu

convective and stratiform development and, consequently, has been increasingly used for MCS classification studies in recent years. On the basis of an 11-yr reflectivity dataset, for example, Bluestein and Jain (1985) documented four distinct formation modes of severe squall lines in Oklahoma during the spring: broken line, back building, broken areal, and embedded areal. This radar-based classification was later extended to nonsevere squall-line development by Bluestein et al. (1987) . Blanchard

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Brian F. Jewett and Robert B. Wilhelmson

shear of a “representative” inflow sounding still largely determine the outcome? Does long-lived forcing matter once the convection has formed, with its attendant strong updrafts, downdrafts, and cold pool? This study addresses the role of persistent forcing in the early development and structure of deep convective squall lines. Two-dimensional forcing was selected for its relative simplicity (conceptually and through numerical simulation), here taken to be a cold front, formed and evolving as an

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Matthew D. Parker

1. Introduction Squall-line maintenance and intensity have been studied for some time (e.g., Newton 1950 ), with an emerging understanding that the convective region of many squall lines occurs along the downshear edge of their outflow boundaries. Early numerical experiments (e.g., Hane 1973 ; Thorpe et al. 1982 ) helped to quantify the impacts of vertical wind shear upon such squall lines. Decades of observations and simulations were reviewed by Rotunno et al. (1988

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John H. Marsham, Stanley B. Trier, Tammy M. Weckwerth, and James W. Wilson

waves (e.g., Marsham and Parker 2006 ) can each lead to the initiation of deep convection, with the most complete theoretical understanding probably existing for initiation by density currents ( Rotunno et al. 1988 ). In this paper we describe the evolution of an MCS that crossed Oklahoma on 13 June 2002. The MCS formed from a merger of four separate episodes of elevated nocturnal convection initiated ∼(100–200) km apart, which became organized into northwest–southeast-oriented lines

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Richard P. James, J. Michael Fritsch, and Paul M. Markowski

lines, leading to conceptual models that focus particularly on the mesoscale characteristics of these linear convective systems (e.g., Zipser 1977 ; Leary and Houze 1979 ; Houze et al. 1989 ; Rasmussen and Rutledge 1993 ). As a tool to study mesoscale convective systems, numerical models have become extremely useful and are generally considered capable of accurately reproducing at least their mesoscale structure and evolution ( Weisman et al. 1997 ). To date, however, the convective

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Tobias Becker and Cathy Hohenegger

deep convection in different tropical regions? Throughout the tropics, the characteristics of deep convective systems depend on the large-scale conditions they are embedded in. In this section we give a brief overview of the key characteristics of convection and its large-scale environment for the five considered regions, before investigating variations in entrainment rate in the next section. The NARVAL domain hosts squall lines over West Africa, organized deep convective clusters associated with

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