A blanket of clouds covers a swollen Subernarekha in Jamshedpur on Wednesday. (Bhola Prasad)

Heavy rainfall in the last 24 hours, particularly in and around Jamshedpur, has ratcheted up the rain surplus figure in the state.

The weather office in Jamshedpur recorded 74.2mm of rain between 8.30am on Tuesday and Wednesday. In Met parlance, 70mm and above is considered heavy rainfall. Adjoining areas like Seraikela and Ghatshila recorded more than 60mm. Ranchi and Daltonganj, too, witnessed showers, receiving 13mm and 8.4mm respectively.

Several other districts including Dhanbad, Hazaribagh, Koderma, Deoghar and Simdega also received some rain during the same period.

Weather analysts said the heavy rainfall in Jamshedpur and its adjoining areas was due to the formation of dense convective clouds. “The wind pattern helped in cloud formation,” said Animesh Chanda, a senior weather analyst and director of the Patna Meteorological Office.

However, he ruled out formation of a low pressure or cyclonic circulation in the Chotanagpur plateau region.

Chanda said widespread rainfall was expected in the next 48 hours as the axis of the monsoon trough was passing over Jharkhand. He said satellite pictures indicated that the monsoon trough line had descended to the lower layers of the atmosphere and this could trigger heavy rain at a few isolated places over the next 48 hours.

So far this monsoon, the state has recorded 788.4mm of rain against an average normal of 702.7mm, a 12 per cent surplus. Till August 11, the figure was 4 per cent.

City-wise figures are equally impressive. Ranchi has so far recorded 1,057.9mm of rain against an average normal of 682mm, a surplus of 55 per cent, while Jamshedpur recorded 1,072.4mm against an average normal of 749 mm, a surplus of 30 per cent. The surplus rainfall at heat chamber Daltonganj is pegged at 14 per cent. Against a normal of 657.1mm, Daltonganj has so far recorded 746.3mm of rain.

In fact, this August has been the wettest in Ranchi in the last five years. Between August 1 and August 17 this year, the local meteorological office in Ranchi recorded 498.4mm rainfall, against an average of 200mm.

Similarly, August has been the wettest in Jamshedpur in the last three years. The local meteorological office has recorded 389.3mm of rain so far in August against an average of 235.5mm.

According to P.D. Sen, a meteorologist at the local weather office, if the current rainfall trend continues, the rain-o-meter is expected to touch the 600mm mark by the end of this month.

“Conditions are favourable for more rain. The humidity is ranging between 85 and 90 per cent in Jamshedpur and its adjoining areas, which is an indication of more rain,” he added.