The Southwest monsoon has become weak over Jharkhand due to shifting of the trough towards north but weathermen on Wednesday extended the alert for thunderstorm and lightning in a few isolated pockets, along with heavy rain, in the northern districts after the next 48 hours.

“Southwest monsoon activity was weak over Jharkhand during the past 24 hours. It will continue to remain weak for another 48 hours till the afternoon of June 26. After this, heavy rain is expected in the northern Jharkhand districts, which are close to the Bihar border due to formation of a convergence zone,” said S.D. Kotal, the director of Ranchi Meteorological Centre.

Kotal said a convergence zone is formed due to flow of moisture-laden winds from the Bay of Bengal.

“The moisture condenses into clouds and results in heavy and widespread rain,” he said, adding that atmospheric instability increases due to formation of a convergence zone.

The districts which are expected to get heavy showers are Godda, Jamtara, Pakur, Dumka, Dhanbad and Deoghar.

College students on a hot and humid day in Dhanbad on Wednesday Picture by Gautam Dey

The Met department issued a bolt alert for northern and south eastern parts of Jharkhand. Reports of lightning poured in from some parts of the state on Wednesday afternoon, including Ramgarh, Hazaribagh, northern Ranchi, Chatra and Latehar.

Light to moderate rain was reported at a few places in the last 24 hours.

Jamshedpur recorded rainfall of 26.8mm while Panchet near Dhanbad recorded 25mm. Chandil in Seraikela-Kharsawan district and Rajmahal in Sahebganj district recorded 20mm of rain.

Several places in Bokaro and Koderma districts recorded 10mm rainfall in 24 hours (8.30am on Tuesday to 8.30am on Wednesday).

The northern limit of monsoon (NLM) was passing through Jaisalmer, Pali, Sawai Madhopur and Pathankot on Wednesday.

Weathermen said due to weakening of the monsoon, several districts would experience sultry weather, which in turn will push up the discomfort index.

The average discomfort index, measured on the basis of temperature, humidity and wind patterns, was 58 degrees, three degrees above normal, in Jharkhand on Wednesday.

A climate analyst at IMD’s Ranchi office said the weather would be slightly warm and humid for the next two days.

Statistics of monsoon rain revealed that so far Jharkhand has received 159.1mm against a normal of 138.4mm, a surplus of 15 per cent.