ISLAMABAD: After around 20pc above normal rainfall in August, the Met Office has warned of above average downpours in September too.

The monthly average rainfall in September is 123mm whereas Islamabad has already received 91mm in the five days of the month. Light to heavy rainfall is expected in Rawalpindi and Islamabad up to Tuesday.

The average rainfall in Islamabad in August is 334.7mm whereas the capital city received 398.7mm last month. But there are higher chances of flooding in September.

The monsoon season lasts up to Sept 15 and the Met Office said the first half of the month is expected to be wetter than the second one, with all the water bodies already filled to their capacity.

“The monsoon season starts in July and ends in mid-September but after the two dry months of May and June, all precipitation is absorbed by the vegetation, earth, rivers, canals and lakes. Even buildings and structures absorb water in July,” said an official of the Met Office, adding all such bodies were filled to the capacity in August and water was surplus by September.

The global climate model indicates a weak La-Niña and non-significant negative Indian Ocean Dipole (IOD) during September which will cause a relative warm and humid climate conditions over the country.

The Met Office predicted unexpected variations of a regional weather pattern over South Asia, including Pakistan, due to these developments.

While in August moisture was transported from the Arabian Sea which caused heavy rainfall and urban flooding in the coastal belt of Sindh, including Karachi, the monsoon low pressure over the Bay of Bengal in September coupled with the seasonal low pressure over Balochistan is likely to cause rainfall in central and southern parts of the country.

There are chances of below the average precipitation across Gilgit-Baltistan and upper half of KP while above normal rainfall may occur in central Punjab and eastern Sindh and normal rainfall in AJK.

As there will be a clear sky over southern parts of Sindh, there are high chances of above normal temperatures in these areas, including Karachi and southern parts of Balochistan.

Published in Dawn, September 6th, 2020