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Qin Xu and Shouting Gao

into a single parameter--the normalizedEkman number. The algebraic equations are shown to be useful for diagnoses or local forecasts of cold air damming providedthe external parameters are properly estimated from the operational analyses or predictions. Examples of application are given for three cases of cold air damming.1. Introduction Cold air damming (Richwien 1980) [or mountainbarrier jet (Schwerdtfeger 1975) ] is a mesoscale phenomenon commonly occurring during the late fall andwinter

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K. J. Tory, M. T. Montgomery, and N. E. Davidson

5 . 2. TC-LAPS: Model description LAPS is an operational Numerical Weather Prediction (NWP) forecast model. A number of domains of varying sizes and horizontal resolution are run twice daily, together with a global model, to make up the suite of NWP forecasts produced by the Australian Bureau of Meteorology. The largest LAPS domain is illustrated in Fig. 1 . It encompasses the Australian continent and much of the surrounding oceans and seas, and neighboring islands (longitude 65.0° to 184

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Mark DeMaria and Wayne H. Schubert

.Because of this, the errors in the storm intensity using the control simulation as a perfect forecast are aboutthe same for the adiabatic and diabatic initializations. This indicates that the usefulness of the standardMachenhauer initialization in tropical cyclone models may be limited. The diabatic initialization schemeused in the ECMWF operational model is also tested. For this case, the time-averaged diabatic forcing isdetermined from a short model run and then held fixed during the iteration. For

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Kevin Wolf, André Ehrlich, Mario Mech, Robin J. Hogan, and Manfred Wendisch

measurements and may not represent all possible ice cloud types ( Fu 1996 ; Baum et al. 2005a , b ). In numerical weather prediction (NWP) and global climate models (GCM), ice clouds contribute substantially to model uncertainty and are the components with the lowest confidence ( Waliser et al. 2009 ; Bauer et al. 2015 ; Stevens and Bony 2013 ). Therefore, advanced ice cloud parameterizations and model updates are required. A leading example for continuous model improvement is the Integrated Forecast

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J. L. Kinter III, J. Shukla, L. Marx, and E. K. Schneider

-August period (MJJA simulation). In each case, seasonally varying boundary conditions of sea surface temperature, soil moisture and ~ ice were used, The computer code used was nearly identical to that used by NMC for the operational ten-day forecast during the period 16 April 1985 through 30 May 1986. Both simulations have been compared to the NMC analyses for the corresponding period. it was found that the model climatology, defined as the avei'age over the last 3 months of each run, is similar to that

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Francesca Di Giuseppe and Adrian M. Tompkins

datasets employed and processing assumptions made. The wind information is derived by locating the 25-km grid point of the ECMWF operational Integrated Forecast System (IFS) that contains each individual 1.1-km column in the CloudSat overpass (the nearest-neighbor method is used, and no spatial interpolation is applied). The vertical profile of zonal and meridional winds u and υ from the closest 6-hourly analysis time is projected onto the satellite overpass track and then averaged in the along

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Hua Leighton, Sundararaman Gopalakrishnan, Jun A. Zhang, Robert F. Rogers, Zhan Zhang, and Vijay Tallapragada

the rate of loss of angular momentum to the surface via surface friction, spinup occurs. High-resolution forecast models have also provided insights on the three-dimensional intensification problem in a sheared environment (e.g., Chen and Gopalakrishnan 2015 , hereafter CG2015 ; Nguyen and Molinari 2015 ). In CG2015 , the authors used the operational Hurricane Weather Research and Forecasting (HWRF) system to verify predictions of Hurricane Earl (2010) against available inner-core observations

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Michael Oczkowski, Istvan Szunyogh, and D. J. Patil

project is more than scientific curiosity. Several important studies (and also some operationally implemented techniques) are based on the implicit assumption that errors in the shortand early medium-range (1–4 days) forecasts evolve in a low-dimensional space. For instance, the general success of the now operational targeted weather observation programs ( Szunyogh et al. 2000 , 2002b ; Toth et al. 2001 , 2002 ) is a strong indication that low-dimensional regions may play a crucial role in the

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K. J. Tory, N. E. Davidson, and M. T. Montgomery

period of development is essential for genesis, TC-LAPS (an operational model initialized every 12 h) may have to rely on the initialization scheme to capture such development after it has occurred. This could have forecasting implications in the Atlantic basin where enhanced evaporation in the dry Saharan air layer may favor stratiform dynamics in MCSs. Despite these perceived misgivings, preliminary results have shown TC-LAPS has had qualitative success in the Indian Ocean, northwest, southwest

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Jon M. Schrage, Andreas H. Fink, Volker Ermert, and Epiphane D. Ahlonsou

be shown in this study, the presence of a single special radiosonde station in Parakou, Benin, during the rainy season 2002 led to a substantial improvement in the representation of the low-level flow and moisture field in the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis. This station was operated by the Integrated Approach to the Efficient Management of Scarce Water Resources in West Africa (IMPETUS) project. Additionally, a number of automated weather stations and a dense

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