The Flood Forecasting Division issued a Chenab-Jhelum flood alert, warning of high levels at Marala Headworks and Mangla Dam during heavy rain expected from July 20 to 24.
The division said rainfall in India and Kashmir could significantly increase inflows into the Chenab River at Marala and the Jhelum River near the Mangla Dam site.
High flooding is also possible in the Kabul River and nearby streams, according to the forecast.
The Flood Forecasting Division warned that drains connected to the Chenab and Jhelum river systems could overflow during the wet spell.
Flash floods may affect local streams and nullahs in Kashmir, Murree, Galiyat, northeastern Punjab, Islamabad, Khyber Pakhtunkhwa and Gilgit-Baltistan.
The warning also covers hill torrents in Dera Ghazi Khan and northeastern Balochistan, where intense rainfall may trigger sudden water flows.
Urban flooding is possible from July 20 to 23 in Islamabad-Rawalpindi, Peshawar, Gujranwala, Lahore, Sialkot, Multan and Faisalabad.
Read: Heavy Rain in Lahore Hits Several Areas, 18.2mm Recorded
Residents in low-lying areas, riverbanks and along routes near seasonal streams should follow official evacuation and traffic instructions issued by district administrations and disaster management authorities.