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Purpose of Review What does recent work say about how changes in convective organization could lead to changes in extreme precipitation? Recent Findings Changing convective organization is one mechanism that could explain variation in extreme precipitation increase through dynamics. In models, the effects of convective self-aggregation on extreme precipitation are sensitive to parameterization, among other factors. In both models and observations, whether or not convective organization influences extreme precipitation is sensitive to the time and space scales analyzed, affecting extreme precipitation on some scales but not others. While trends in observations in convective organization associated with mean precipitation have been identified, it has not yet been established whether these trends are robust or relevant for events associated with extreme precipitation. Summary Recent work has documented a somewhat view of how changes in convective organization could affect extreme precipitation with warming, and it remains unclear whether or not they do.

Purpose of Review: Review our current understanding of how precipitation is related to its thermodynamic environment, i.e., the water vapor and temperature in the surroundings, and implications for changes in extremes in a warmer climate. Recent Findings: Multiple research threads have i) sought empirical relationships that govern onset of strong convective precipitation, or that might identify how precipitation extremes scale with changes in temperature; ii) examined how such extremes change with water vapor in global and regional climate models under warming scenarios; iii) identified fundamental processes that set the characteristic shapes of precipitation distributions. Summary: While water vapor increases tend to be governed by the Clausius-Clapeyron relationship to temperature, precipitation extreme changes are more complex and can increase more rapidly, particularly in the tropics. Progress may be aided by bringing separate research threads together and by casting theory in terms of a full explanation of the precipitation probability distribution.

Purpose of Review There is concern that extreme weather events may become stronger, more frequent, or both as the climate changes. This paper seeks more clarity in defining different types of extreme storms, and the global distribution of each type. Recent Findings Detailed case studies of specific events over the United States are revealing but the only way to document such occurrences globally is by using radar profiles from the GPM core satellite. Recent results differ somewhat depending on specific definitions and approaches, but they are starting to converge. Summary We demonstrate the global distribution of the ~ 1000 most extreme events of each type over a 5-year period and find that in addition to testing for extreme rain rates and extremely intense convection, we must also differentiate by size. Large rain areas containing extreme rates are exclusively oceanic, small rain areas often have extreme rates over land. The most intense convective cores are almost exclusively over land, regardless of size.

Purpose of Review This review focuses on recent progress in understanding the extratropical influence on the annual- and zonal-mean intertropical convergence zone (ITCZ) position using a hierarchy of model simulations and theory. Recent Findings Significant progress in our theoretical understanding of the zonal-mean ITCZ position has been made utilizing simulations with a slab ocean. Interhemispheric contrasts in the atmospheric heating (e.g., via an anomalous radiative forcing in one hemisphere) lead to a compensating cross-equatorial energy transport by Hadley circulation adjustments and corresponding meridional ITCZ shifts. In particular, high-latitude radiative perturbations have a strong influence on the ITCZ position. The effectiveness of extratropical forcing for resulting in ITCZ shifts is amplified by cloud radiative feedbacks in the midlatitudes and tropical water vapor feedback associated with the ITCZ displacement. However, more recently conducted fully coupled model simulations tend to show a less pronounced extratropical influence on the ITCZ position due to additional compensating effects from ocean dynamics. The oceanic damping effect on ITCZ shifts results from distinct ocean circulation components, including the Atlantic Meridional Overturning Circulation and the wind-driven subtropical cell. Both the relative importance of different ocean circulation components and the roles of different radiative feedbacks are sensitive to forcing location, making the tropical hydroclimate response to extratropical forcing sensitive to the geographical location of the forcing, for instance, in which ocean basin it occurs. The interaction between radiative feedbacks and ocean dynamical adjustment further confounds the determination of extratropical influence on the ITCZ position, which has motivated a recently initiated model intercomparison project. Summary The zonal-mean energetics framework needs to be refined to explain beyond the time- and zonal-mean ITCZ position so as to incorporate transient propagation features and the spatial distribution of the tropical precipitation response.