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David R. Ryglicki, Daniel Hodyss, and Gregory Rainwater

change in the orientation of the rotational axis of a rotating body, of the vortex tilt ( Jones 1995 , 2000 ; Schecter et al. 2002 ; Reasor et al. 2004 ; Schecter 2015 ; Reasor and Montgomery 2015 ). These nutations produce features in satellite imagery identified as tilt-modulated convective asymmetries (TCA). TCAs are distinct cloud structures that are separate from the diurnal signal ( Kossin 2002 ), pulse with a periodicity of 4–8 h on the left-of-shear side of the TC core, and do not rotate

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

-mean tangential winds (RMW) of 90 km. It also has a Gaussian-like decay in the vertical with the maximum wind speed at z = 1500 m. The environmental shear profile and how it is introduced in the model are described below. b. Time-varying point-downscaling method The large-scale environmental shear is incorporated into the model using the point-downscaling method (PDS; Nolan 2011 ). Using PDS, the initial environmental flow is balanced by an artificial force that is added to the momentum equation so that

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Patrick Duran and John Molinari

possible that a vertical grid spacing even smaller than 250 m is necessary to resolve cloud-top radiative tendencies. Meanwhile below the tropopause, time-mean radiative warming was present between the 30- and 160-km radii within the cirrus canopy. The existence of radiative cooling overlying radiative warming in this region led to radiatively forced destabilization at and below the tropopause, as was depicted in Fig. 7d . Beneath the warming layer existed a region of forcing for stabilization, while

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

-level forcing mechanism), and this study identifies and quantifies a set of key common features for this class of TCs. The analyses in this study primarily rely on satellite observations, since these data typically provide the most complete spatial and temporal coverage over the storms, given that aircraft observations of TCs are rare in the eastern North Pacific (EPAC) and western Pacific (WPAC; Knabb et al. 2008 ). Without in situ reconnaissance data, intensity estimations and analyses are primarily

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

) . Cloud-free radiative cooling could also be a potential mechanism for explaining the intensity differences between the Fullrad and Nightonly simulations ( Gray and Jacobson 1977 ). In the Nightonly simulations the enhanced cloud-free environmental subsidence driven by longwave cooling in the outer environment could force stronger inflow into the TC; however, no substantial differences were present in the outer-core radiative cooling rates over 24-h means (not shown). Due to the short time scale of

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

-modulated convective asymmetry (TCA). TCAs, as diagnosed by cloud-top temperatures colder than −70°C, are cloud structures that are responsible for approximately 10 000–15 000-km 2 changes in cloud cover, that expand upshear, and, most importantly for the purposes of this study, that appear with periods between 4 and 8 h. A series of numerical simulations in this second part are analyzed to quantify further the dynamics and characteristics, including the vertical structure, of this class of TCs that undergo RI in

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

scan a full Earth disk at 10-min intervals. The spatial resolution is also enhanced to 0.5 km for band 3 in the visible wavelength, and the two other visible bands and band 4 in the near-infrared have 1-km resolution. Two other near-infrared bands and all infrared bands have a spatial resolution of 2 km. The infrared band 11 is used for detection of thin ice cloud such as is often found at the edge of the TC cirrus outflow, and infrared band 16 is used for cloud-top height assignment. The three

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David R. Ryglicki, James D. Doyle, Daniel Hodyss, Joshua H. Cossuth, Yi Jin, Kevin C. Viner, and Jerome M. Schmidt

ventilating TCs, inducing a potential vorticity–related spinup, and outright shearing of the TC, depending on the proximity of the upper-level synoptic forcing. Vertical wind shear (VWS) is generally a negative influence on TC intensification ( Merrill 1988b ; Wang and Wu 2004 ). Recent studies on wind shear’s negative effects have focused on the thermodynamic effects of VWS, such as the midlevel ventilation ( Tang and Emanuel 2010 ; Tang and Emanuel 2012 ; Ge et al. 2013 ) or the flushing of the

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Patrick Duran and John Molinari

), the coldest temperature, −86°C, was observed a few hundred meters above the highest cloud tops ( Waco 1970 ). Very near the storm center, the temperature at 16.5-km altitude increased from −86° to −77°C over a horizontal distance less than 30 km as the aircraft approached the storm center [see Fig. 2 “Run 2” in Waco (1970) ]. This strong inward temperature increase was likely associated with an intense upper-tropospheric warm core within and near Beulah’s eye. The presence of a warm core in the

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