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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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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

, S. , D. M. Schultz , and G. Vaughan , 2017a : Early evolution of the 23–26 September 2012 U.K. Floods: Tropical Storm Nadine and diabatic heating due to cloud microphysics . Mon. Wea. Rev. , 145 , 543 – 563 , https://doi.org/10.1175/MWR-D-16-0200.1 . 10.1175/MWR-D-16-0200.1 Hardy , S. , D. M. Schultz , and G. Vaughan , 2017b : The 23–26 September 2012 U.K. Floods: Using PV surgery to quantify sensitivity to upper-level forcing . Mon. Wea. Rev. , 145 , 4055 – 4079 , https

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

offshore by the vortex outer circulation (>100 km from the center) and advected upward ( Chan and Liang 2003 ). When dry air moves over moist air, this reduces the moist static stability on the offshore side, and an asymmetric convection and cloud pattern is expected ( Chan and Liang 2003 ). Subsequently, when a TC moves closer to the shore and is situated partly over land and partly over the ocean, the difference in surface roughness has a dominant effect on vertical motion asymmetries, compared to

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

error tendency equation. Our tendency equation is based on the local tendency equation for PV in isentropic coordinates, which is given by (e.g., Davies and Didone 2013 ) where describes the nonconservative PV tendency due to diabatic heating and nonconservative momentum change as measured by the parameterization schemes. The heating rate comprises heating due to the cloud, convection, radiation, and turbulence parameterization, while the horizontal wind tendency components of ( and

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