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Patrick A. Reinecke and Dale R. Durran

. The lateral boundary conditions on the 27-km domain are specified from operational forecasts of the Naval Operational Global Atmospheric Prediction System (NOGAPS) and perturbed for each ensemble member using the fixed-covariance-perturbation method described in Torn et al. (2006) . The perturbations are Gaussian with zero mean and a covariance that is balanced for synoptic-scale motions. The covariance relations are obtained from the Weather Research and Forecasting-Variational (WRF-VAR) data

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Vanda Grubišić and Brian J. Billings

conditions were specified using the Naval Operational Global Atmospheric Prediction System (NOGAPS) forecast fields, which were applied every 6 h throughout all simulations. The simulation consisted of a 12-h spinup run initialized at 1200 UTC 23 March, and three subsequent 24-h runs initialized at 0000 UTC 24, 25, and 26 March. The initial fields for the 24-h runs were created by blending the previous COAMPS forecast with the NOGAPS analysis and available operational upper-air soundings and surface data

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Bowen Zhou and Fotini Katopodes Chow

numerical modeling over complex terrain: Operational applications. Mountain Meteorology: Bridging the Gap between Research and Forecasting, Springer, 591–653.

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James D. Doyle, Vanda Grubišić, William O. J. Brown, Stephan F. J. De Wekker, Andreas Dörnbrack, Qingfang Jiang, Shane D. Mayor, and Martin Weissmann

of the downslope wind speed and wave-breaking characteristics as diagnosed from idealized mesoscale ensemble forecasts (e.g., Doyle and Reynolds 2008 ). 6. Conclusions We have explored the dynamics and internal structure of mountain-wave-induced rotors during T-REX IOP 13 through the use of a suite of ground-based and airborne observing platforms and very high-resolution simulations using a large-eddy simulation version of the nonhydrostatic COAMPS model. The observations and model results

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James D. Doyle and Dale R. Durran

low-level rotor, resulted in the loss of an engine on a commercial United Airline Boeing 747–100 at 600-m AGL near Anchorage, Alaska ( Kahn et al. 1997 ). In spite of their clear significance to the meteorology and aviation communities, the dynamics and structure of rotors are poorly understood and forecasted, in part because of infrequent and insufficient observational measurements, and inadequate sophistication and fidelity of numerical weather prediction models. Mountain waves and rotors were

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Ivana Stiperski and Vanda Grubišić

instability of steady mountain waves . J. Fluid Mech. , 568 , 303 – 327 . Louis , J. F. , 1979 : A parametric model of vertical eddy fluxes in the atmosphere . Bound.-Layer Meteor. , 17 , 187 – 202 . Louis , J. F. , M. Tiedtke , and J. F. Geleyn , 1982 : A short history of the operational PBL parameterization at ECMWF . Proc. Workshop on Planetary Boundary Layer Parameterization, Reading, United Kingdom, European Centre for Medium-Range Weather Forecasts, 59–79 . Mayr , G. J. , and A

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