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Yun Lin, Jiwen Fan, Jong-Hoon Jeong, Yuwei Zhang, Cameron R. Homeyer, and Jingyu Wang

weather and climate based on the National Climate Assessment ( Brown et al. 2014 ), including studies of Baker et al. (2002) , Grimmond (2007) , Hallegatte and Corfee-Morlot (2011) , and Rosenzweig et al. (2010) , etc. The majority of past studies related to the impacts of urbanization on weather have focused on temperature (e.g., Kalnay and Cai 2003 ; Hale et al. 2008 ) and precipitation (e.g., Shepherd 2005 ; Kaufmann et al. 2007 ; Kishtawal et al. 2010 ; Han et al. 2014 ; Liu and Niyogi

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Stacey M. Hitchcock and Russ S. Schumacher

layer so no moisture modifications (e.g., Peters and Schumacher 2015b ), or forced large-scale lifting ( Crook and Moncrieff 1988 ; Loftus et al. 2008 ; Schumacher 2009 ) was needed to initiate convection. Instead, four 1-K warm bubbles with a 10-km horizontal and 1-km vertical radius and spaced 20 km apart were used. Passive tracers were placed in the lowest 500 m at the start of the simulation in order to help identify stable air lifted by updrafts. Passive tracers were also placed in the layer

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Samuel K. Degelia, Xuguang Wang, and David J. Stensrud

1. Introduction Convection initiation (CI) refers to the process in which an air parcel is successfully lifted to its level of free convection (LFC) and produces a precipitating updraft ( Markowski and Richardson 2010 ). At night in the Great Plains of the United States, CI commonly contributes to a nocturnal maximum in summer precipitation (e.g., Surcel et al. 2010 ). Nocturnal CI in the Great Plains also leads to thunderstorms that produce all severe weather hazards ( Grant 1995 ; Horgan et

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Aaron Johnson and Xuguang Wang

Convection at Night (PECAN) field experiment took place in 2015 with the purpose of collecting comprehensive and targeted observations of bores and other phenomena related to nocturnal convection ( Geerts et al. 2017 ). One use of these unprecedented observations is the ability to validate the details of model simulated bores to better understand the sensitivities and sources of error in numerical weather prediction (NWP) involving bores. For example, Johnson et al. (2018) used data from the 11 July

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Samuel K. Degelia, Xuguang Wang, David J. Stensrud, and Aaron Johnson

. 1979 ) that often result in more deaths in the United States per year than any other severe weather-related hazard ( NOAA 2004 ). Considering the well-documented nocturnal maximum in precipitation in the Great Plains of the United States ( Wallace 1975 ; Surcel et al. 2010 ), improving forecasts of nocturnal convection during the summer is crucial. Previous studies have related the nocturnal precipitation maximum to the eastward movement of mesoscale convective systems (MCSs) that initiate over

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Hristo G. Chipilski, Xuguang Wang, and David B. Parsons

et al. 2017 ). The dynamical significance of convective outflow boundaries has prompted the scientific community to create automated algorithms for identifying and tracking these features. The earliest algorithm developed for this purpose was entirely based on observational data and closely connected to the procurement plans for the Next Generation Weather Radar (NEXRAD) system (e.g., Crum and Alberty 1993 ). In particular, Uyeda and Zrnić (1986) as well as Smith et al. (1989) were the first

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Tammy M. Weckwerth, Kristy J. Weber, David D. Turner, and Scott M. Spuler

1. Introduction There is a long-standing and certain need for improved atmospheric moisture measurements within and just above the atmospheric boundary layer (BL; defined here to be the lowest 2–3 km above the earth’s surface). Several recent National Research Council (NRC) reports highlighted the requirement for improved moisture and wind measurements in the BL as a necessary step toward improving numerical weather prediction (NWP) and quantitative precipitation forecasting (QPF) skill ( NRC

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Matthew D. Flournoy and Michael C. Coniglio

) and mesoscale convective vortices (MCVs; e.g., Menard and Fritsch 1989 ; Cotton et al. 1989 ), which are typically 20–200 km in length and can persist for several hours. Mesovortices are typically most intense near the surface (1–2 km AGL), thus explaining their association with straight-line surface wind damage and, occasionally, tornadoes. This inherent severe weather threat associated with mesovortices has made them the subject of many studies, which have yielded multiple theories as to how

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Alan Shapiro, Evgeni Fedorovich, and Joshua G. Gebauer

1. Introduction It has long been recognized that warm season precipitation over the central United States exhibits a nocturnal maximum ( Kincer 1916 ; Bleeker and Andre 1951 ; Means 1952 ; Pitchford and London 1962 ; Wallace 1975 ; Easterling and Robinson 1985 ; Riley et al. 1987 ; Dai et al. 1999 ; Carbone et al. 2002 ; Carbone and Tuttle 2008 ). This rainfall is beneficial for agriculture, but it is also associated with lightning, flooding, and other weather hazards ( Crysler et al

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David B. Parsons, Kevin R. Haghi, Kelton T. Halbert, Blake Elmer, and Junhong Wang

, several studies (e.g., Davis et al. 2003 ; Clark et al. 2007 ; Surcel et al. 2010 ) have demonstrated that advancing forecast skill in numerical weather prediction models for these nocturnal systems has proven elusive. The low skill is important, since researchers have long established that summer thunderstorms and convective precipitation are most frequent after sunset over a broad region of the Great Plains, ranging from Oklahoma to southern Manitoba, and between about 92° and 100°W ( Kincer 1916

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