ISLAMABAD - Pakistan Meteorologi­cal Department (PMD) has advised the authori­ties concerned to remain vigilant during the heavy downpour expected to generate urban flooding in Karachi and Hyder­abad and flash flood­ing in hill torrents of Khuzdar on Friday or Saturday. According to the spokesman of PMD, a monsoon low pres­sure from Bay of Bengal approached Sindh on Thursday night causing penetration of monsoon currents in Sindh, South Punjab and Eastern Balochistan till Satur­day. Widespread rain/wind-thundershowers, with isolated heavy to very heavy falls were expected in Karachi, Hy­derabad, Thatta, Badin, Tharparker, Umerkot, Mirpurkhas, Sanghar, Tando Allah Yar, Mati­yari, Tando Muhammad Khan, Jamshoro, Dadu and Shaheed Benazi­rabad during the next 24 hours. Scattered rain-thundershowers with isolated heavy falls are also expected in Baha­walpur, Rahim yar Khan, Khairpur, Sukkur, Larka­na, Kambarshahdad Kot, Jacobabad, Kashmore, Ghotki, Kalat, Jaffarabad, Jhalmagsi, Khuzdar, Las­bella and Awaran on Fri­day and Saturday. During the last 24 hours, hot and very humid weather pre­vailed over most parts of the country. How­ever, rain-wind-thun­dershowers occurred in Kashmir, Punjab and Khyber Pakhtunkhwa.