The abbreviation "kt" commonly stands for "kiloton," which is a unit used to measure the power or energy released by explosive devices like nuclear bombs. Full definition
White Shell Necklace, Shell Choker, Mother of Pearl, Iridescent White, 14 Kt Gold Fill, White Shell Choker, MOP Necklace (etsy.com)
Remember that 879 hPa match with 155 kt in the pressure - wind relationship used in the Indian Ocean, the South Pacific and the western North Pacific. (realclimate.org)