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Oreste Reale, William K. Lau, Kyu-Myong Kim, and Eugenia Brin

European Centre for Medium Range Weather Forecasts (ECMWF) so-called nature run (a 13-month-long simulation in free running mode performed with the then-operational ECMWF model at the horizontal resolution of T511, corresponding to approximately 40 km) and verified that the simulation contained quasi-realistic AEW activity and a realistic number of Atlantic tropical cyclones. Strictly speaking, the resolutions adopted by the previously referenced studies cannot yet be considered adequate to resolve the

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Zhaoxia Pu, Xuanli Li, and Juanzhen Sun

1. Introduction Hurricanes are one of the nature’s most intense phenomena and one of the coastal resident’s greatest fears. They threaten the maritime industry, devastate coastal regions, and cause floods and erosion inland through torrential rainfall, high winds, and severe storm surges. As suggested by Landsea (1993) , hurricane damage increases exponentially with the low-level wind speed. Therefore, accurate forecasting of hurricane intensity changes near their landfall is of great

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Edward K. Vizy and Kerry H. Cook

the National Center for Atmospheric Research–National Oceanic and Atmospheric Administration (NCAR–NOAA) Advanced Research Weather Research and Forecasting model (ARW-WRF) and National Aeronautics and Space Administration observations taken in support of the African Monsoon Multidisciplinary Analyses (AMMA) field campaign. Background on the conditions necessary for tropical cyclogenesis is reviewed in section 2 . Section 3 describes the regional model and the modeling approach. In section 4

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Syed Ismail, Richard A. Ferrare, Edward V. Browell, Gao Chen, Bruce Anderson, Susan A. Kooi, Anthony Notari, Carolyn F. Butler, Sharon Burton, Marta Fenn, Jason P. Dunion, Gerry Heymsfield, T. N. Krishnamurti, and Mrinal K. Biswas

were studied during NAMMA, three of which intensified to form Tropical Storms Debby and Ernesto and Hurricane Helene ( Zipser et al. 2009 ). An examination of the SAL in the NAMMA domain indicated that the SAL was a quasi-steady-state feature, with significant modulations of aerosol content and a periodicity of ∼5 days from 15 August to 15 September 2006. There were only three minor (1–2 day) breaks when the SAL was not overspreading the NAMMA study region. However, satellite imagery and forecasts

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Zhuo Wang, M. T. Montgomery, and T. J. Dunkerton

: the wide range of spatial scales has been computationally prohibitive. Until now, only a subset of scales has been accessible, encompassing the storm domain only, while observations of tropical cyclogenesis in tropical easterly waves suggest a multiscale process (e.g., Gray 1998 ). Inspired by careful study of weather analyses and discussions posted by Tropical Analysis and Forecast Branch (TAFB) forecasters at the U.S. National Hurricane Center (NHC), DMW09 developed a new framework for TC

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Chanh Q. Kieu and Da-Lin Zhang

1. Introduction The life cycle of tropical cyclones (TCs) is typically divided into the following four phases: pregenesis with little closed circulation, tropical depression (TD), tropical storm (TS), and hurricane. Of the four, the pregenesis and its subsequent growth to TD and TS stages, the so-called tropical cyclogenesis (TCG), are the most difficult phases to predict by numerical TC models and operational forecasters. Despite the many processes involved during TCG, the recent successes of

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John Molinari and David Vollaro

Medium-Range Weather Forecasts (ECMWF) above the dropsonde release point, interpolated from the model grid to the release point location; and (ii) adjusting the ECMWF values at all levels by a constant equal to the difference between the interpolated ECMWF value and the dropsonde value at their first common level. The second step resembles that used by Bogner et al. (2000) . MV08 used the first step but not the second, which then required additional procedures for correcting discontinuities. The

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Zhuo Wang, M. T. Montgomery, and T. J. Dunkerton

section 2 . Section 3 examines the formation of the warm-core structure. The evolution of stratiform and deep convective precipitation and their respective contribution is examined in section 4 . Section 5 presents a modest suite of sensitivity tests, followed by discussions and conclusions in section 6 . 2. Model and sensitivity experiments The Weather Research and Forecasting (WRF) model version 3.0 ( Skamarock et al. 2005 ) was used in this study, and the model was described briefly in Part

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Robert Rogers

1. Introduction One of the most challenging problems in tropical cyclone (TC) forecasting is predicting TC intensity change. While track forecasts have improved markedly in the past 20 years, progress in intensity forecasting has lagged significantly behind ( Rogers et al. 2006 ; DeMaria et al. 2005 ). Intensity forecasting is challenging because the processes important in intensity change occur within and between scales of many orders of magnitude, including environmental, vortex, convective

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Jonathan Zawislak and Edward J. Zipser

GDAS uses a T254 Gaussian grid, equivalent to a 1° × 1° latitude/longitude grid spacing with global coverage. The GDAS archive provides fields four times daily (0000, 0600, 1200, and 1800 UTC) for the following variables at 64 vertical pressure levels: temperature, height, absolute vorticity, vertical velocity, relative humidity, and u and υ wind. The analyses are produced by using the current analysis to initialize the Global Forecast System (GFS), which then produces 3-, 6-, and 9-h forecasts

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