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Kevin Bachmann, Christian Keil, George C. Craig, Martin Weissmann, and Christian A. Welzbacher

hours ( Hohenegger and Schär 2007a , b ; Zhang et al. 2015 , 2016 ). However, there are steady Earth surface features such as orography or transient dynamical forcing patterns such as weather regimes that potentially provide the means to extend those predictability estimates ( Anthes 1986 ). The prevailing synoptic weather regime exerts a decisive influence on the predictability of convective precipitation. In case studies, Hanley et al. (2011 , 2013) and Barrett et al. (2015) showed how the

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Mirjam Hirt, Stephan Rasp, Ulrich Blahak, and George C. Craig

relevant when synoptic forcing is weak and local mechanisms are the main driver for overcoming convection inhibition ( Keil et al. 2014 ). In these situations insufficient convective initiation has been commonly observed for kilometer-scale models (see e.g., Clark et al. 2016 ). In operational NWP systems such biases are often compensated by tuning other parameters, such as the turbulent length scale in the boundary layer parameterization ( Hanley et al. 2015 ). Smaller mixing lengths allow the lowest

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Jacopo Riboldi, Christian M. Grams, Michael Riemer, and Heather M. Archambault

trough and the strength of the downstream impact ( Scheck et al. 2011a , b ; Grams et al. 2013a ; Riemer and Jones 2014 ). This is most likely due to an enhanced potential for reintensification of the transitioning TC as an extratropical cyclone. Ahead of a trough, the storm may be located in a region of positive vorticity advection and forcing for ascent in the vicinity of a low-level baroclinic zone, a setup conducive to Petterssen–Smebye Type-B cyclogenesis ( Klein et al. 2002 ; Ritchie and

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Hilke S. Lentink, Christian M. Grams, Michael Riemer, and Sarah C. Jones

Research and Predictability Experiment (THORPEX) Pacific Asian Regional Campaign (T-PARC). Measurements from three aircrafts provide a unique dataset for detailed analysis of structural development during ET. Between 0100 and 0600 UTC 19 September and between 0500 and 0900 UTC 20 September, the research aircrafts Naval Research Laboratory P-3 and the U.S. Air Force WC-130 flew through the central region to obtain measurements of the eyewall. The DLR-Falcon was operating in the environment northeast of

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Volkmar Wirth, Michael Riemer, Edmund K. M. Chang, and Olivia Martius

and E have been created during that time. c. Different types of RWPs and their propagation There are different types of RWPs associated with different temporal and spatial scales, different types of forcing, and specific properties of the background flow. Sometimes an RWP is little more than an individual trough or ridge ( Sanders 1988 ); sometimes an RWP may span a substantial part of the globe ( Branstator 2002 ). Some RWPs propagate along great circles, while others are ducted in the zonal

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Julia H. Keller, Christian M. Grams, Michael Riemer, Heather M. Archambault, Lance Bosart, James D. Doyle, Jenni L. Evans, Thomas J. Galarneau Jr., Kyle Griffin, Patrick A. Harr, Naoko Kitabatake, Ron McTaggart-Cowan, Florian Pantillon, Julian F. Quinting, Carolyn A. Reynolds, Elizabeth A. Ritchie, Ryan D. Torn, and Fuqing Zhang

cyclone constitutes an external forcing with persistent structure to the midlatitude wave. This idea is in marked contrast to traditional initial-value studies of baroclinic development, in which the initial perturbations are embedded in the midlatitude flow and are thus not an external forcing (e.g., Simmons and Hoskins 1979 ; Hakim 2000 ). 2) Evolution of the upstream trough ET may also influence the upstream trough, which may experience modifications of its shape, meridional extension, and

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Gabriel Wolf and Volkmar Wirth

.g., Dritschel and McIntyre 2008 ). A strong gradient of potential vorticity, in turn, represents a strong restoring force for parcels away from its unperturbed trajectory, which guarantees close to linear wave behavior. The jet in this context is considered to be part of the background flow, and to the extent that the jet makes some gentle excursions in the meridional direction, the RWP follows these excursions on its otherwise zonal and eastward trajectory. Anomalies due to the RWPs are measured with

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Marlene Baumgart, Michael Riemer, Volkmar Wirth, Franziska Teubler, and Simon T. K. Lang

-0315.1 Moncrieff , M. W. , D. E. Waliser , and J. Caughey , 2012 : Progress and direction in tropical convection research: YOTC International Science Symposium . Bull. Amer. Meteor. Soc. , 93 , ES65 – ES69 , . 10.1175/BAMS-D-11-00253.1 Nie , Y. , Y. Zhang , G. Chen , and X.-Q. Yang , 2016 : Delineating the barotropic and baroclinic mechanisms in the midlatitude eddy-driven jet response to lower-tropospheric thermal forcing . J. Atmos. Sci

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