The state capital is set to experience the first wet weekend this monsoon, courtesy a cyclonic circulation.

Prevailing over Jharkhand, it is likely to arrive in Patna by Saturday morning. As a result, there is a forecast of heavy downpour in the state capital in the next couple of days.

Ashish Sen, the director (radar) of India Meteorological Department (IMD), Patna, told The Telegraph: “The cyclonic circulation prevailing over Jharkhand has led to heavy downpour in that state in the past few days. It is heading towards Bihar, which is expected to cause moderate to heavy rainfall in the next two to three days in over half the state.”

According to the afternoon bulletin of the IMD, southwest monsoon has covered the entire state. Though the skies remained mostly overcast in the city after the arrival of the monsoon on June 19, the rainfall has been scanty so far.

The monsoon was delayed by about six days this year. Usually, it sets in between June 11 and 13.

The rainfall in the state between June 1 and 21 was also below normal this year. It has been 54.5mm against the expected 105mm — a deficit of 48 per cent.

Similarly, the actual rainfall in Patna district between June 1 and June 21 was 20.8mm against the expected rainfall of 79.2mm — a deficit of 74 per cent.

The weathermen, however, claimed that the upcoming cyclonic circulation in Bihar might turn the entire rainfall scenario upside down.

“The cyclonic circulation prevailing over Jharkhand caused 480 per cent surplus rainfall on Thursday itself. Such heavy rain on a single day has reduced the rainfall deficiency from 50 per cent on Thursday morning to 24 per cent on Friday morning. It is likely to have a similar impact on Bihar as well. Even two days of heavy downpour can make up for the deficient rainfall being observed till date,” said Sen.

He attributed the deficient rainfall in Bihar to negligible pre-monsoon showers in June and the late arrival of monsoon.

Few weather scientists claimed that the cyclonic circulation would be more effective in the southern parts of Bihar. “Only south Bihar, especially the districts adjacent to Jharkhand, would receive heavy downpour. North and central Bihar would receive light to moderate rainfall,” said Adbus Sattar, an assistant professor of meteorology at Rajendra Agriculture University, Samastipur.