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Patrick A. Reinecke and Dale Durran

crest by 9% relative to that in the continuous solution. Representative dimensional parameters for this problem are given on line 2 of Table 2 and are typical of resolutions that may be present in operational NWP forecasts. The gridpoint locations relative to the mountain are shown in Fig. 1 and are identical to those in the previously considered δ = 1.8 case. A less well-resolved case is shown in Fig. 4c , in which the normalized horizontal resolution is Δ x ′ = 1.35, corresponding to

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James D. Doyle, Qingfang Jiang, Ronald B. Smith, and Vanda Grubišić

. Lateral boundary conditions for the outer most grid mesh are based on the Navy Operational Global Analysis and Prediction System (NOGAPS) forecast fields. Two types of real data forecasts and simulations are performed in this study. The first set of COAMPS forecasts was performed in real time using three horizontally nested grid meshes of 91 × 91, 133 × 133, and 157 × 157 grid points with horizontal grid increments on the computational meshes of 18 km, 6 km, and 2 km, respectively. The real

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Shiyuan Zhong, Ju Li, C. David Whiteman, Xindi Bian, and Wenqing Yao

western Nevada that resulted in extensive damage. For both cases, the model was able to capture the mountain waves believed to be responsible for the high winds. The operational Eta Model, in comparison, failed to forecast these high wind events, leading to the conclusion that a grid spacing of 5 km or less is necessary to predict high wind events in the complex terrain of the Sierra Nevada. The severe windstorms in the lee of the Sierra Nevada are generally believed to be associated with mountain

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Qingfang Jiang and James D. Doyle

Harshvardhan et al. (1987) . The initial fields for the model are created from multivariate optimum interpolation analysis of upper-air sounding, surface, commercial aircraft, and satellite data that are quality controlled and blended with the 12-h COAMPS forecast fields. Lateral boundary conditions for the outermost grid mesh are derived from Navy Operational Global Analysis and Prediction System (NOGAPS) forecast fields. The computational domain contains four horizontally nested grid meshes (i.e., one

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James D. Doyle, Saša Gaberšek, Qingfang Jiang, Ligia Bernardet, John M. Brown, Andreas Dörnbrack, Elmar Filaus, Vanda Grubišić, Daniel J. Kirshbaum, Oswald Knoth, Steven Koch, Juerg Schmidli, Ivana Stiperski, Simon Vosper, and Shiyuan Zhong

operational WRF-NMM at NCEP . Preprints, 21st Conf. on Weather Analysis and Forecasting/17th Conf. on Numerical Weather Prediction, Washington, DC, Amer. Meteor. Soc., 4B.4. [Available online at http://ams.confex.com/ams/pdfpapers/94734.pdf .] Bretherton , F. P. , 1969 : Momentum transport by gravity waves . Quart. J. Roy. Meteor. Soc. , 95 , 213 – 243 . Brinkman , W. A. R. , 1974 : Strong downslope winds at Boulder . Mon. Wea. Rev. , 102 , 592 – 602 . Bryan , G. H. , and J. M. Fritsch

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Vanda Grubišić and Brian J. Billings

forecasters, climatologists, mesoscale and regional climate modelers, and for selecting optimal sites and timing of observational field campaigns, 1 existence of such climatologies is clearly important. Additionally, availability of climatologies for different mountain ranges that are known for the generation of lee waves ( Auer 1992 ; Mitchell et al. 1990 ; Smith 1976 ; Vosper and Mobbs 1996 ) would allow for easier generalization of physical process study findings obtained in one region to other

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Juerg Schmidli, Brian Billings, Fotini K. Chow, Stephan F. J. de Wekker, James Doyle, Vanda Grubišić, Teddy Holt, Qiangfang Jiang, Katherine A. Lundquist, Peter Sheridan, Simon Vosper, C. David Whiteman, Andrzej A. Wyszogrodzki, and Günther Zängl

1. Introduction Over mountain areas the evolution of the boundary layer is particularly complex as a result of the interaction between boundary layer turbulence and thermally induced mesoscale wind systems, such as the slope and valley winds (e.g., Rotach et al. 2008 ). As the horizontal resolution of operational forecasts progresses to finer resolution, a larger spectrum of thermally induced wind systems can be explicitly resolved. It is therefore useful to document the current state

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Qingfang Jiang and James D. Doyle

fields. Lateral boundary conditions for the outermost grid mesh are derived from Navy Operational Global Analysis and Prediction System (NOGAPS) forecast fields. The computational domain contains four horizontally nested grid meshes of 91 × 91, 131 × 131, 157 × 157, and 256 × 256 grid points, and the corresponding horizontal grid spacings are 27, 9, 3, and 1 km, respectively. There are 55 levels in the vertical on a nonuniform sigma grid with finer spacing in the lower troposphere. The model top is

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Yanping Li, Ronald B. Smith, and Vanda Grubišić

Valley observations from the Terrain-Induced Rotor Experiment (T-REX) project. In section 4 we propose a novel approach for estimating the valley daily maximum mixed-layer depth using surface pressure and temperature amplitudes. Idealized 2D Weather Research and Forecasting Model (WRF) simulations are described in section 5 , together with a discussion of the physical processes involved in producing surface pressure and temperature variations in mountain valleys. Section 6 gives the results of

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Christian Kühnlein, Andreas Dörnbrack, and Martin Weissmann

, whereas the width of the valley is ~15 km. The next section briefly describes the overall meteorological evolution during IOP6. The Doppler lidar observations are presented in section 3 . Conclusions will be provided in section 4 . 2. Synoptic weather situation and upstream profiles The temporal evolution of the meteorological situation during IOP6 is depicted in Fig. 1 by means of 6-hourly European Centre for Medium-Range Weather Forecasts (ECMWF) analyses of geopotential height, wind, and

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