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Jie Feng and Xuguang Wang

1. Introduction Over the past few decades, great efforts have been made to improve the accuracy of tropical cyclone (TC) forecasts. The major endeavors include the development of high-resolution cloud-resolving numerical weather prediction (NWP) models, advanced data assimilation (DA) systems, and novel observing systems for TCs. So far, the accuracy of TC analysis and prediction has been steadily and significantly improved. For example, the yearly averaged track forecast at the 5-day lead time

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David R. Ryglicki, Daniel Hodyss, and Gregory Rainwater

primarily rotational without a prominent divergent component and that the pressure anomaly caused by a modification of the tornado’s rotation was neglected. A TC possesses a large and significant divergent flow field, and this divergent flow is what is necessary to divert the environmental flow around the TC upwind. This creates an interesting paradox with regard to shear calculations used both operationally and academically. Many works have tried to remove the vortex in various ways to ascertain the

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Yi Dai, Sharanya J. Majumdar, and David S. Nolan

section 3 , followed by a statistical analysis in section 4 that confirms the findings from the idealized simulations. Conclusions are provided in section 5 . 2. Methodology a. Model configuration The Weather Research and Forecasting (WRF; Skamarock et al. 2008 ) Model, version 3.9.1, is used for the idealized simulations. The framework comprises three nested domains with horizontal grid spacings of 18, 6, and 2 km; and domain sizes of 10 800 km × 7200 km, 2298 km × 2298 km, and 768 × 768 km

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Xu Lu and Xuguang Wang

speed (Vmax), and minimum sea level pressure (MSLP)] ( Thu and Krishnamurti 1992 ; Kurihara et al. 1995 , 1998 , Liu et al. 2000 , 2006 ; Pu and Braun 2001 ; Tallapragada et al. 2014 ). In the National Oceanic and Atmospheric Administration (NOAA) operational Hurricane Weather Research and Forecasting system (HWRF), vortex initialization (VI) contains two components: vortex relocation (VR) and vortex modification (VM), where VR corrects the storm location and VM modifies the storm intensity

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Benjamin C. Trabing, Michael M. Bell, and Bonnie R. Brown

(RCE), and as such the impact of upper-tropospheric temperature modification on intensity has primarily been evaluated on long time scales >100 days in RCE ( Emanuel et al. 2013 ). Ramsay (2013) analyzed the effects of colder tropopause temperatures on TC intensity using a nonhydrostatic, axisymmetric, cloud-resolving model in RCE over 120 days. Ramsay found that the maximum intensity of their 2D simulated TCs increased by 1 m s −1 K −1 cooling of the prescribed tropopause temperature and

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Quanjia Zhong, Jianping Li, Lifeng Zhang, Ruiqiang Ding, and Baosheng Li

predictability of TC intensity ( Emanuel and Zhang 2016 ). TC intensity is not only affected by the large-scale environment, but also by complex physical processes, making it difficult to assess error growth and intrinsic predictability. Many studies of the predictability of TC intensity have used the Weather Research and Forecasting (WRF) Model ( Zhang et al. 2014 ; Tao and Zhang 2015 ; Zhu et al. 2016 ), idealized axisymmetric models ( Hakim 2011 , 2013 ; Kieu and Moon 2016 ), and statistical

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Robert G. Nystrom and Fuqing Zhang

. Super observations are created in real time at the NOAA Hurricane Research Division based on the methodology described in Weng and Zhang (2012 , 2016) . Briefly, super observations are created by averaging radial velocity observations, obtained from forward and backward scans from the NOAA P-3 Tail Doppler Radar, within a trapezoid that is 5 km in the radial direction by 5° in the azimuthal direction. One modification to the PSU WRF EnKF real-time system is that the data assimilation cycles are

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David R. Ryglicki, Joshua H. Cossuth, Daniel Hodyss, and James D. Doyle

preexisting, synoptic-scale anticyclones. The physical significance of the anticyclones is the vertical structure of the environmental winds. As was shown by Hoskins et al. (1985) and Wirth (2001) , upper-level anticyclonic PV anomalies are much shallower in the vertical when compared with their cyclonic counterparts, given the same thermal anomaly magnitude and the same radial size. Figure 8 is a slight modification of Fig. 15 from Hoskins et al. (1985) , comparing an idealized upper-level cyclonic

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David R. Ryglicki, James D. Doyle, Yi Jin, Daniel Hodyss, and Joshua H. Cossuth

. Montgomery , and M. E. Nicholls , 2010 : A new paradigm for intensity modification of tropical cyclones: Thermodynamic impact of vertical wind shear on the inflow layer . Atmos. Chem. Phys. , 10 , 3163 – 3188 , https://doi.org/10.5194/acp-10-3163-2010 . 10.5194/acp-10-3163-2010 Riemer , M. , M. T. Montgomery , and M. E. Nicholls , 2013 : Further examination of the thermodynamic modification of the inflow layer of tropical cyclones by vertical wind shear . Atmos. Chem. Phys. , 13

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Russell L. Elsberry, Eric A. Hendricks, Christopher S. Velden, Michael M. Bell, Melinda Peng, Eleanor Casas, and Qingyun Zhao

restricted domains and durations. More importantly, applications in numerical weather prediction (NWP) have often been constrained to 6-h data assimilation cycles and AMV dataset thinning. In this study it will be demonstrated that shorter sampling times and continuous rapid scanning combined with the advanced sensors on these new-generation satellites will substantially improve the quality and quantity of the AMVs, and thus their potential impacts on the U.S. Navy regional and global model analyses and

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