A meteorological condition when the tropospheric circulation takes the form of large-amplitude stationary waves, possibly lasting for weeks. The upper air flow then guides depressions around the edge of the anticyclone(s). Renwick and Revell (1999) Month. Weath. Rev. 127, 10 suggest that Rossby wave propagation links anomalous convection in the tropics and blocking over the south-east Pacific Ocean. Blocking anticyclones develop when the Rossby pattern changes from zonal to strongly meridional, often forming one or two high-level, closed anticyclonic circulations. Athar et al. (2013) Int. J. Climatology 33, 3, 585 report that 31% of the Northern Hemisphere mid‐latitude blocking anticyclone events occurred over the 10°–70° E longitudes, and of these, the maximum number of mid‐latitude blocking anticyclone event onsets are at 30° E (24%); see Schopf et al. (1981) Dyn. Atmos. Oceans 5.