The India Met Department (IMD) has flagged a fresh low-pressure area over the North-West Bay of Bengal under watch for intensification by tomorrow (Thursday).
The ‘low’ has formed largely out of the internal dynamics of the Bay, after the Arabian Sea arm of the monsoon remained subdued over the last couple of days.
This also explains why a dry spell over the peninsula continues even as the ‘low’ is about to kick off fresh rain into most parts of the North-East, East India and North-West India.
Heavy rain forecast
An active monsoon trough and likely strengthening of easterlies from the Bay could cause widespread rainfall with isolated heavy falls over parts of Madhya Pradesh during the next three days.
A similar forecast is valid for Uttar Pradesh for two days and East Rajasthan, Haryana, Chandigarh and Delhi on Friday and Saturday. The foothills of the Himalayas are likely to receive enhanced rainfall on Sunday and Monday.
In the shorter term, the IMD has forecast widespread rainfall with isolated very heavy and extremely heavy falls over Odisha during the next two days. The adjoining plains of Bengal, Jharkhand and Chhattisgarh are also likely to receive widespread rainfall with isolated heavy falls during this period.
In a detailed forecast, the IMD said heavy to very heavy rain with extremely heavy falls may lash Odisha, while Jharkhand will see heavy to very heavy rain.
Heavy rain is forecast over Uttarakhand, Uttar Pradesh, East Rajasthan, Madhya Pradesh, Assam, Meghalaya, Nagaland, Manipur, Mizoram, Tripura, plains of Bengal and north Coastal Andhra Pradesh.
The ‘low’ will set up ‘rough’ to ‘very rough’ sea conditions over the North Bay off Odisha, Bengal and Bangladesh coasts. Fishermen are advised not to venture into the sea in these areas.
Quiet over peninsula
An outlook for Thursday said that heavy to very heavy rain with extremely heavy rainfall is likely over Odisha, while it will be heavy to very heavy over Chhattisgarh; heavy rain is also forecast over the plains of Bengal, Jharkhand, Uttarakhand, Uttar Pradesh and Madhya Pradesh.
As the cross-equatorial flow, bringing in monsoon winds from the Southern Hemisphere into the Arabian Sea and the Bay continues to remain weak, rainfall over Peninsular India could remain subdued during the next five days, the IMD said. A tell-tale atmospheric feature in the form of a North-South trough extending up to 1.5 km above mean sea level from South Interior Karnataka to the Comorin area across interior Tamil Nadu persisted. This is at best a feature associated with pre-monsoon conditions and goes to signal the complete absence of any monsoonal activity over large parts of the peninsular India.
The Met subdivisions of Rayalaseema (-46 per cent) and North Interior Karnataka (-23 per cent) as well as the Lakshadweep Islands (-44 per cent) could witness the prevailing rain deficits grow further during this period.
Haryana, Chandigarh and Delhi (-20 per cent each) and West Rajasthan (-21 per cent) have fallen into a deficit; Jharkhand improved to -21 per cent; while Saurashtra and Kutch worsened to -25 per cent. The overall deficit for the country as a whole is -7 per cent.