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David J. Stensrud and Steven J. Weiss

the spacing of sigma levels reduced near the ground surface to simulate better the evolution of the planetary boundary layer (PBL). The model is initialized for each day at 0000 UTC using the National Centers for Environmental Prediction (NCEP) Eta Model ( Black 1994 ) forecast fields available at 25-hPa vertical intervals and with 40-km grid spacing, bilinearly interpolated to the MM5 grid points at selected pressure levels. A static initialization is performed, in which the pressure-level data

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Xuejin Zhang, Sundararaman G. Gopalakrishnan, Samuel Trahan, Thiago S. Quirino, Qingfu Liu, Zhan Zhang, Ghassan Alaka, and Vijay Tallapragada

convection-permitting resolution was transitioned into operations in 2012 ( Tallapragada et al. 2014 ; Goldenberg et al. 2015 ). The forecast system incorporated a movable multilevel nesting (MMLN) algorithm with planetary boundary layer (PBL) and surface physics carefully calibrated using available in situ observations obtained from the hurricane inner-core region ( Gopalakrishnan et al. 2013 ) and an improved vortex initialization scheme documented in the online HWRF scientific documentation. 1 The

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Bao-Fong Jeng, Hway-Jen Chen, Shwu-Ching Lin, Tzay-Ming Leou, Melinda S. Peng, Simon W. Chang, Wu-Ron Hsu, and C.-P. Chang

theatmosphere, leads to a heating of the atmosphere. Thebackscattered solar radiation does not heat the atmosphere, but is used to determine the soil temperaturein Eq. (18). REFERENCESAnthes, R. A., 1977: A cumulus parameterization scheme utilizing a one-dimensional cloud model. Mon. Wea. Rev., 105, 270 286. ,1983: Regional models of the atmosphere in middle latitudes. Mon. Wea. Rev., 111, 1306-1335.Betts, A. K., and M. J. Miller, 1986: A new convective adjustment scheme. Part II

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Talmor Meir, Philip M. Orton, Julie Pullen, Teddy Holt, William T. Thompson, and Mark F. Arend

City has an area of 790 km 2 , a population of 8 million, and contains five boroughs that are all influenced by the marine coastal atmosphere. NYC lies at the center of a broader urban and suburban metropolitan region, with Long Island extending to the east and New Jersey and the city of Newark to the west and southwest. Both NJ and Long Island are bordered by the coastal waters of the Atlantic ( Fig. 1 ). NYC and its surrounding urbanized region generate a pronounced urban heat island (UHI) effect

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Travis H. Wilson and Robert G. Fovell

cooling effectively shuts off ( Zhou and Ferrier 2008 ). It has been shown that with sufficient fog-top longwave divergence, the upper part of a fog layer can destabilize ( Bergot et al. 2007 ). With time, the destabilization can continue until nearly the entire fog profile is moist adiabatic ( Holets and Swanson 1981 ; Boers et al. 2013 ). This creates atmospheric conditions quite similar to stratocumulus-capped planetary boundary layers (PBLs) where cloud-top cooling via radiative flux divergence

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Maria J. Molina, John T. Allen, and Andreas F. Prein

trajectory per tornado report and analogous to previous studies (e.g., Gustafsson et al. 2010 ; Erlingis et al. 2019 ; Molina and Allen 2019 ), a three-dimensional matrix consisting of 11 × 11 × 11 points (1331 total) was released (per tornado report) and centered at the height of the planetary boundary layer (HPBL). This matrix method was done to account for some uncertainty in air mass dispersion from turbulent fluxes and trajectory sensitivity to the gridded nature of reanalysis data ( Stohl 1998

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Michael C. Coniglio, Kimberly L. Elmore, John S. Kain, Steven J. Weiss, Ming Xue, and Morris L. Weisman

the following day; the same nominal time of the initial analysis) are 1.2–1.8 times larger compared to the initial time, which is smaller than the error growth for the TMP850 and WSHR ( Figs. 3c and 3f ). This relatively slow growth in the model error of fields that are directly impacted by the planetary boundary layer (PBL) evolution compared to the typical growth of errors in larger-scale flows in the free atmosphere ( Simmons et al. 1995 ; Wandishin et al. 2001 ) is found in Mass et al. (2002

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Feng Gao, Xiaoyan Zhang, Neil A. Jacobs, Xiang-Yu Huang, Xin Zhang, and Peter P. Childs

, and wind direction. We further analyze the error in both wind speed, as well as direction, as a function of the speed itself. Additionally, we follow strict collocation match conditions as described in Benjamin et al. (1999) for the purpose of minimizing the representativeness error; however, even with this protocol, any time a numerical model representation of the atmosphere is constructed based on observations, an associated space–time representativeness error of that observation will be

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Gareth J. Marshall and John Turner

accurate, sharper pressure gradients and deeper low pressure centers in the former using pressure fields derived from a planetary boundary layer model. However, Ingleby and Bromley (1991) revealed that while the assimilation of Seasat winds into the U.K. Meteorological Office (UKMO) forecast model resulted in the largest global pressure differences from a control run (without the winds) being observed in the data-sparse SH, such deviations were not necessarily beneficial to forecast accuracy. More

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Ji-Young Han and Song-You Hong

) planetary boundary layer (PBL) scheme ( Hong et al. 2006 ), and the Global/Regional Integrated Model System (GRIMs) shallow convection scheme ( Hong et al. 2012 ). An updated version of the simplified Arakawa–Schubert (SAS) deep convection scheme is used as a CP. The CP used in this study is a mass-flux scheme based on the SAS convection scheme ( Pan and Wu 1995 ; Han and Pan 2011 ), but with several modifications to the subgrid-scale cloud properties that has been revised by the Korea Institute of

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