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.