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Ariel E. Cohen, Steven M. Cavallo, Michael C. Coniglio, and Harold E. Brooks

of turbulence closure models for planetary boundary layers . J. Atmos. Sci. , 31 , 1791 – 1806 , doi: 10.1175/1520-0469(1974)031<1791:AHOTCM>2.0.CO;2 . Mellor, G. L. , and Yamada T. , 1982 : Development of a turbulence closure model for geophysical fluid problems . Rev. Geophys. Space Phys. , 20 , 851 – 875 , doi: 10.1029/RG020i004p00851 . Monin, A. S. , and Obukhov A. M. , 1954 : Basic laws of turbulent mixing in the surface layer of the atmosphere (in Russian ) . Tr. Geofiz

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Ariel E. Cohen, Steven M. Cavallo, Michael C. Coniglio, Harold E. Brooks, and Israel L. Jirak

1. Introduction Accurately representing turbulent processes occurring within the planetary boundary layer (PBL) of the lower troposphere is of particular importance for the southeast U.S. cold season severe thunderstorm environment ( Cohen et al. 2015 , hereafter CCCB15 ). In southeast U.S. cold season severe thunderstorm environments (hereafter SECOLD), thermodynamic instability is often limited amid ample vertical wind shear, and the marginality of thermodynamic instability for the SECOLD

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S. B. Trier, M. A. LeMone, F. Chen, and K. W. Manning

exchange strength on convection initiation and short-range (e.g., 0–24 h) QPFs. Overall effects of land–atmosphere coupling on warm-season precipitation have also been widely explored in atmospheric general circulation models. There, land–atmosphere coupling on seasonal time scales has been established as an important factor determining predictability in certain regions (e.g., Koster et al. 2004 , 2006 ). Similar studies for 0–24-h forecasts are less common, which may be partly related to the

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Douglas K. Miller

low-level atmospheric moisture, temperature, and stratification ( Perry and Konrad 2006 ; Holloway 2007 ; Keighton et al. 2009 ). Observations of clouds generating NWFS by a vertically pointing micro–rain radar ( Yuter and Perry 2007 ; Keighton et al. 2009 ) indicate that they are extremely shallow, with tops rarely exceeding 2000 m above ground level. The mesoscale variability of the low-level atmosphere is due in part to the different synoptic conditions that generate NWFS events. Perry et

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Dorita Rostkier-Edelstein and Joshua P. Hacker

. , Brown P. D. , Iacono M. J. , and Clough S. A. , 1997 : Radiative transfer for inhomogeneous atmosphere: RRTM, a validated correlated-k model for the long-wave . J. Geophys. Res. , 102 ( D14 ), 16 663 – 16 682 . Murphy, A. H. , 1973 : A new vector partition of the probability score . J. Appl. Meteor. , 12 , 595 – 600 . Noh, Y. , Cheon W. G. , Hong S. Y. , and Raasch S. , 2003 : Improvement of the k -profile model for the planetary boundary layer based on large eddy

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Jongil Han and Hua-Lu Pan

eliminating the instability and consequently causing explicit convective ascent to occur on the grid scale. To this end, the scheme was modified to make the cumulus convection stronger and deeper. The old operational nonlocal planetary boundary layer (PBL) scheme in the NCEP GFS [the so-called Medium-Range Forecast (MRF) PBL model] proposed by Troen and Mahrt (1986) and implemented by Hong and Pan (1996) has been widely used for vertical diffusion because it not only provided a realistic development

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Robert G. Fovell and Alex Gallagher

in the planetary boundary layer (PBL), a highly parameterized region that can serve as a significant source of forecast error, is much more sparse in time and/or space, more difficult to obtain and manipulate, and can also be subject to contamination (e.g., Daniel et al. 1999 ; Walters et al. 2014 ). Furthermore, comparisons often focus on integrated or averaged metrics such as 500-hPa height or liquid water path rather than the vertical structure of the PBL. This study emerged from a need to

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Young-Joon Kim and Maria Flatau

1. Introduction Sudden stratospheric warming (SSW) is an abrupt disruption of the stratospheric winter circulation involving a rapid breakdown of the polar vortex. SSW is triggered by anomalous planetary (Rossby) wave activity propagating from the troposphere, and it is characterized by a rapid increase of the polar stratospheric temperature (about 40 K in a week) and a reversal of the stratospheric polar night jet. An SSW event is called “major” if the 10-hPa (or below in height) zonal mean

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Paul A. Dirmeyer and Subhadeep Halder

1. Introduction It is accepted that the state of the land surface can influence the atmosphere across a range of time scales, thanks to a number of weather and climate modeling studies. Most studies have focused on soil moisture, as it has the largest impact on subseasonal-to-seasonal time scales. Furthermore, the focus has been on time scales of weeks or months, out to seasonal scales, as it has been assumed that weather forecasts (on the order of hours to a few days) are an atmospheric

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Thomas E. Rosmond

.2 ), increasing computer resource requirements nearlythreefold. Tight operational run-time schedules andcomputer memory size make any further resolutionTABLE 1. NOGAPS description.Computational Details Resolution: Triangular truncation --Operational: T79; 18 levels --Research: T47, T63; 18 levels Semi-implicit time differencing Implicit zonal advection --Vorticity --Moisture Silhouette orography Computer --CYBER 205:1988-1991 --CRAY YMP: 1991-FutureDiabatic Processes Planetary boundary layer

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