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Aaron Johnson and Xuguang Wang

) and Rapid Radiative Transfer Model for GCMs (RRTMG; Mlawer et al. 1997 ) longwave radiation schemes, and the Noah ( Ek et al. 2003 ) land surface model. The forecasts are on the convection-permitting 4-km domain ( Fig. 1 ), so no cumulus parameterization is used. In addition to the deterministic forecasts described above, three experiments are performed using different PBL configurations during DA and 20-member ensemble forecasts to evaluate the analysis quality ( Table 2 ). The three experiments

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Sean Stelten and William A. Gallus Jr.

consolidated into a disorganized MCS ( Figs. 2c,d ). Among the WRF runs, only the ACM2 PBL run did not produce the type 1 CI event at all ( Figs. 15j–l ). Because the Pleim–Xiu land surface scheme must be used when the ACM2 PBL scheme is used instead of the Noah land surface model used in the other three configurations, sensitivity tests were run with the other three PBL schemes also using the Pleim–Xiu scheme for the 24 June case. Simulations were not sensitive to this change in the land surface scheme

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Aaron Johnson and Xuguang Wang

Johnson et al. (2015) , Johnson and Wang (2017) , Johnson et al. (2017) , and Wang and Wang (2017) . The ensemble mean analysis on the 1-km domain is used to initialize the deterministic forecasts evaluated in this study. The forecast model is version 3.8 of the WRF ARW. All forecasts use the WSM6 ( Hong and Lim 2006 ) microphysics scheme, Noah ( Ek et al. 2003 ) land surface model, and Dudhia (1993) shortwave and RRTM ( Mlawer et al. 1997 ) longwave radiation schemes. Forecasts that use a

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Aaron Johnson, Xuguang Wang, Kevin R. Haghi, and David B. Parsons

source of initial and lateral boundary condition perturbations. All members use Noah land surface scheme ( Ek et al. 2003 ) and RRTMG radiation ( Mlawer et al. 1997 ). In this study, assimilation of surface and upper-air observations from the operational National Centers for Environmental Prediction (NCEP) data stream on the 12-km domain is conducted every 3 h from 0300 UTC 10 July through 0000 UTC 11 July. NEXRAD observations, together with the North American Mesoscale Forecast System (NAM) model

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

during its ascent. These soundings are launched operationally worldwide but typically only twice a day (normally at 0000 and 1200 UTC) per site and the sites are separated by hundreds of kilometers. They are often not representative of the mesoscale environment needed for improving forecasts of thunderstorms. Satellite retrievals provide global coverage but have poor vertical resolution and limited temporal resolution. Furthermore, satellites commonly use infrared spectral methods to derive water

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Stanley B. Trier, James W. Wilson, David A. Ahijevych, and Ryan A. Sobash

, 2002 ) PBL scheme, the Rapid Radiative Transfer Model for global climate models (RRTMG; Mlawer et al. 1997 ; Iacono et al. 2008 ) longwave and shortwave radiation schemes, and the Noah land surface model ( Chen and Dudhia 2001 ). Figure 8 compares vertical profiles of adjusted diagnosed from observations with corresponding area-averaged from the model ensemble. Since an important criterion used for triangle selection is the absence of significant precipitation within the triangle at the time

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

al. 2007 ), although hail and wind are the most common threats ( Reif and Bluestein 2017 ). Past studies have shown that numerical weather prediction (NWP) models that employ convective parameterizations often underpredict nocturnal convective events in the High Plains of the United States ( Davis et al. 2006 ). Although various deficiencies have been resolved through the use of convection-resolving models ( Weisman et al. 2008 ), many of the mechanisms that initiate convection at night remain

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

both supercells and an MCS in WRF. The Lin scheme has also been shown to perform well for other convective modes (e.g., Nasrollahi et al. 2012 ). Additional sensitivity studies were conducted using various microphysical and PBL parameterization schemes; all schemes produced CI at similar locations and times. The Noah land surface model ( Ek et al. 2003 ), Rapid Radiative Transfer Model for general circulation models (longwave radiation; Iacono et al. 2008 ), Goddard shortwave radiation ( Tao et

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John M. Peters, Erik R. Nielsen, Matthew D. Parker, Stacey M. Hitchcock, and Russ S. Schumacher

IV (ST4) analyzed precipitation ( Fig. 8b ) in the CSUWRF and DSRAP simulations, and approximately 50–100 km northeastward of the stage IV precipitation in the DSNAM. Finally, we analyzed a 10-member ensemble of forecasts with similar configurations to the CSUWRF (e.g., 4-km horizontal grid spacing, Morrison two-moment microphysics, Noah land surface model, see Table 1 ), but with a different member of the Global Ensemble Forecast System (GEFS/R; Hamill et al. 2013 ) used as ICs and LBCs to

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Kevin R. Haghi, Bart Geerts, Hristo G. Chipilski, Aaron Johnson, Samuel Degelia, David Imy, David B. Parsons, Rebecca D. Adams-Selin, David D. Turner, and Xuguang Wang

a bore over the Gulf Coast. (c) “Morning Glory” seen from Virgin Australia flight (courtesy of Virgin Australia, @VirginAustralia). (d) GOES-16 water vapor channel (courtesy of NOAA). (e) Radar reflectivity images of an undular bore over Oklahoma, (courtesy of Noah Brauer, @NOAABrauer). (f) Images of a bore developed from a sea/land breeze interaction (courtesy of @Weatherology Twitter account). Disclaimer: data from GOES-16 data are preliminary. Past studies on organized convection captured

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