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Weiguo Wang, Jason A. Sippel, Sergio Abarca, Lin Zhu, Bin Liu, Zhan Zhang, Avichal Mehra, and Vijay Tallapragada

1. Introduction To adjust the initial vortex structure of a tropical cyclone (TC) in numerical models, limited observations such as flight-level and surface winds in the TC eyewall area are usually interpolated or extrapolated to other levels based on first-guess meteorological fields obtained from model output of previous hours. Therefore, it is important to accurately simulate the vertical profiles of wind in the inner-core area. Vertical diffusion in the planetary boundary layer (PBL) is one

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Sen Chiao and Yuh-Lang Lin

orography will also be examined throughout the entire life cycle of the heavy orographic rainfall event. In section 5 , we conclude this study with a discussion based on our interpretation of the simulation results with particular emphasis on application to orographic precipitation forecasting. 2. Description of the model and experiment design The atmospheric component of the Naval Research Laboratory's (NRL) Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS; Hodur 1997 ) is used in this

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Kevin W. Manning and Christopher A. Davis

by applying to the temperature tendency a cooling term (a weak function of temperature), which amounted to approximately −1.8 K day −1 . No radiative effects of cloud on the atmosphere (e.g., shortwave absorption and scattering; longwave absorption and emission) are considered. Radiative effects of cloud are considered in estimating the radiation budget of the ground. Longwave and shortwave radiational heating and cooling of the ground is parameterized taking into account cloud fractions

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Steven L. Mullen and Bruce B. Smith

form 15 December 1992) ABSTRACT Sea level cyclone errors for two contrasting planetary-scale flow regimes, a long-wave trough verses a longwave ridge over western North America, are computed for the National Meteorological Center's Nested GridModel (NGM) and "Aviation Run" of the Global Spectral Model (AVN). The study is performed for the1987/88 and 1989/90 cool seasons (1 December-31 March). All available 24- and 48-h forecast cycles areanalyzed for North America and

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David H. Bromwich, Richard I. Cullather, and Robert W. Grumbine

Chemistry of the Atmosphere, with principal goals of examining the performance of operational analyses and forecasts for Antarctica and the surrounding sea-ice zone during three 1-month-long SOPs in July 1994, October–November 1994, and January 1995 ( Turner et al. 1996 ). In high southern latitudes, weather data assimilation and prediction face an array of obstacles that limit operational performance, including the scarcity of available data and long-distance communications difficulties. Additionally

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Seung-Eon Lee and Kyong-Hwan Seo

Precipitation Climatology Project (GPCP) for the changma period (15 June–29 July). According to the GPCP, there are three strong precipitation cores (shaded) around the Asian continent: over the South Asia region (i.e., near the Arabian Sea and the Bay of Bengal), in the tropical western North Pacific (WNP), and in the EASM region. The planetary front of the EASM typically occurs over the Bay of Bengal and the South China Sea in May. The front migrates northward and forms a quasi-stationary front in June

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Nicholas A. Bond, Carl F. Dierking, and James D. Doyle

this case have been carried out using COAMPS ( Hodur 1997 ). The model configuration used is summarized in Doyle and Bond (2001) and Doyle et al. (2005) . The parameterization of the planetary boundary layer and free-atmosphere turbulent mixing was likely to be of special relevance for the present application, and so we incorporated the relatively sophisticated scheme based on the level-2.5 formulation of Mellor and Yamada (1982) and Yamada (1983) as modified for implementation within COAMPS

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Rolf H. Langland, Paul M. Tag, and Robert W. Fett

awest to east cross section through simulated surface calm zone (cross section location shown inFig. 2). Ordinate heights are equivalent to levels of model thermodynamic variables.bay. Vertical motion in the sea breeze circulation iscontained below the highly stable layer found above1500 m, the approximate height of the original inversion. Turbulence above the heated land surface produces a well-mixed layer up to about 1100 m, whileover the bay, the atmosphere remains stable, exceptnear the

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David A. R. Kristovich and Neil F. Laird

determined from GOES-8 satellite imagery, obtained from the Cooperative Institute for Research in the Atmosphere (CIRA), Fort Collins, Colorado. A 24-h continuous record of the locations of lake-effect clouds in each of the five cases was determined from IR imagery. High-resolution (1 km) visible imagery (e.g., Fig. 1 ) was used to supplement the IR imagery (4-km resolution) for daylight periods. Time periods when synoptic- and upper-level clouds were present over Lake Michigan were determined from

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A. James Wagner

seasonallyand orographically preferred locations of troughs andridges in the planetary waves, seasonal changes in themean speed of the westerlies and the likely effects onthe circulation, and observed seasonally varying414WEATHER AND FORECASTINGVOLUME 4month-to-month persistence characteristics of monthlymean height and surface weather patterns were all considered as objectively as possible (Namias 1952, 1954).A key element in the forecast was the use of kinematictendencies to show the past and extrapolated

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