The India Meteorological Department (IMD) warned of heavy rain in isolated pockets of Jharkhand during the next five days while neighbouring Bengal was expected to experience heavy to very heavy showers till Sunday.

IMD's Regional Met Centre at Alipore in Calcutta and Ranchi Met Centre issued special bulletins saying the downpour would be due to shifting of the monsoon trough towards the foothills of the Himalayas.

" The intensity of rain would be more in north Bengal districts and places in northern Jharkhand and Bihar which are closer to Himalayas. Whenever the monsoon trough shifts towards the foothills of Himalayas, it results in heavy rain in north Bengal and isolated areas in Bihar and Jharkhand with the intensity of rain reducing in Central India," G. K. Das, director of Alipore Met Centre in Calcutta, explained over telephone.

The rain is expected to be of maximum intensity between Friday, Aug 13 and Sunday, August 15.

Based on the IMD forecast of enhanced rainfall, Bengal government's disaster management department has asked several districts, including Darjeeling, Jalpaiguri, Coochbehar, Alipurduar, Kalimpong, Malda, South 24 Parganas, North 24 Parganas, Nadia, Murshidabad and Birbhum, to remain alert as heavy rain might result in abrupt rise in water levels of rivers, leading to floods and landslides.

IMD's Ranchi Met Centre also issued an alert of heavy rain in isolated pockets of north- eastern Jharkhand (Jamtara, Pakur, Dumka, Giridih and Sahebganj) during the next four days.

Head of Ranchi Met Centre Abhishek Anand said they were expecting heavy showers at a few isolated places in north-western Jharkhand, comprising Daltonganj, Latehar and Garhwa, due to the formation of a cyclonic circulation over eastern Uttar Pradesh extending up to 4.5 km above mean sea level.

The monsoon trough at mean sea level was on Tuesday passing through Amritsar, Kurukshetra, Meerut, Gorakhpur, Muzaffarpur and Jalpaiguri in north Bengal.

High Discomfort Index

Several cities in Jharkhand experienced high discomfort index which is determined on the basis of temperature, humidity, wind pattern and other factors.

The weather remained humid with the sun playing hide and seek. The average discomfort index was as high as 64 degrees, nine degrees above normal, on Tuesday.

In Jamshedpur, the discomfort index was 67 degrees, 12 degrees above normal, and in capital Ranchi, it was 64 degrees, nine degrees above normal. Daltonganj recorded a discomfort index of 62 degrees, seven notches above normal.

In several other districts like Dumka, Ramgarh, Hazaribagh, Pakur, Godda, Latehar, Chatra and Simdega, the index breached 60 degrees.