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Sean Stelten and William A. Gallus Jr.

et al. 2017 ). The present study is centered temporally over the PECAN field phase, but the full study period has been expanded to encompass four warm season months, May–August 2015, to allow for a larger sample of events. A basic climatology of all likely elevated nocturnal CI events during this period is presented to reveal temporal and spatial trends. In addition, both operational and experimental convection-allowing models (CAMs) available to forecasters during the PECAN field phase, as well

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W. G. Blumberg, T. J. Wagner, D. D. Turner, and J. Correia Jr.

trends are occurring (e.g., lifting of a capping inversion) may need to be augmented by radiosondes. Although the vertical resolution of the AERI retrievals may sometimes hinder a precise identification of capping inversions, such issues are overcome in environments where strong vertical gradients and rapid temporal changes occur in the thermodynamic profiles. This feature is particularly favorable for operational meteorologists working challenging convective forecasts with the potential for the

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Guo Lin, Coltin Grasmick, Bart Geerts, Zhien Wang, and Min Deng

an operational network. If the lofted moist plume in Fig. 7a were sampled by chance by an operational radiosonde, it would be assigned a much larger footprint, and thus err data assimilation and forecasts. 5. Bore and solitary waves a. Bore formation and propagation: Observations In addition to CI, the collision between the gust front and cold front also produced a bore-like wave structure with multiple radar fine lines traveling northward on top of the cold-frontal air mass, in the opposite

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Brian J. Carroll, Belay B. Demoz, David D. Turner, and Ruben Delgado

Plains, nocturnal CI (NCI) remains challenging to forecast, especially in the absence of surface boundaries ( Wilson and Roberts 2006 ; Reif and Bluestein 2018 ; Weckwerth et al. 2019 ). This is due in part to the paucity of routine thermodynamic profiling in the PBL and the limited resolution of satellite observations within the lowest few kilometers of the atmosphere ( Kahn et al. 2011 ; Steinke et al. 2015 ; Weckwerth et al. 2019 ). Previous studies based on radiosonde and surface data or

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

aerosol changes jointly and respectively affect hazardous weather events such as hailstones and tornadoes using advanced cloud microphysics and urban canopy parameterizations. The Chemistry version of the Weather Research and Forecasting Model (WRF-Chem) is employed, in which the spectral-bin microphysics (SBM) is coupled with the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC; Gao et al. 2016 ). The multilayer urban canopy model Building Environment Parameterization coupled with

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

. (2018) show improvements to a nocturnal CI forecast by assimilating conventional and radar observations. They find that assimilating these data enhances the buoyancy and convergence prior to CI, while the radar observations aid in suppressing spurious convection and erroneous outflow boundaries. However, the observations assimilated in Degelia et al. (2018) have become routinely assimilated in operational centers and their impacts are now relatively understood. This study expands upon the

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Aaron Johnson, Xuguang Wang, and Samuel Degelia

designed to better understand optimal convection-permitting ensemble forecasts and storm-scale DA configurations for the prediction of nocturnal convection and related features using retrospective forecasts from 2014. The GSI-based multiscale ensemble DA and forecast system described in Part I and Johnson et al. (2015) was also implemented as an operational real-time nocturnal-convection prediction system during the PECAN field experiment. This system is described and evaluated in the present paper

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Aaron Johnson and Xuguang Wang

used in this study. The GSI-based DA system uses a 40-member ensemble based on the Advanced Research version of WRF (ARW) version 3.6.1 with the EnKF configuration described in Johnson et al. (2015) . Conventional surface and upper-air observations from the data stream of the operational North American Mesoscale Forecast System at the National Centers for Environmental Prediction (NCEP), including surface and mesonet stations, Aircraft Communication, Addressing, and Reporting System (ACARS), NOAA

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

responsible for producing convection are fundamentally different after sunset, the impacts of storm-scale DA cannot be assumed to be the same between day and night. This study presents a novel analysis of the impacts that assimilating in situ, as well as radar, observations have on forecasts of an elevated, nocturnal CI event. On 24 June 2013, a late afternoon MCS initiated off a dryline in southwestern Kansas before dissipating in the early evening hours of 25 June ( Fig. 1 ). Operational forecasts for

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

algorithm framework, this paper also highlights a spectrum of additional algorithm applications relevant for bore research and operational forecasting of nocturnal storms. Generally speaking, these algorithm applications can be utilized in two different ways. The first pertains to the verification of numerically simulated convective outflow boundaries. With the advance of convection-allowing NWP models, object-based verification techniques like the Method for Object-Based Diagnostic Evaluation (MODE

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