A fresh low-pressure area has formed over North-West Bay of Bengal this morning, largely out of the internal dynamics of the Bay after the Arabian Sea arm of the monsoon lapsed into a state of silence.
This also explains why a dry spell over Peninsular India continues even as the 'low' is about to kick off fresh rain into most parts of North-East and East India.
Heavy rain forecast
Progressively, parts of adjoining Central and North-West India too could get covered as the 'low' tracks in a west-north-west direction over the plains. In the shorter term, India Met Department (IMD) has forecast fairly widespread to widespread rainfall with isolated very heavy and extremely heavy falls over Odisha during next two days.
Adjoining plains of Bengal, Jharkhand and Chhattisgarh are also likely to receive fairly widespread to widespread rainfall with isolated heavy falls during this period.
The ongoing fairly widespread to widespread rainfall with isolated heavy falls is likely to continue over parts of North-West and adjoining Central India into tomorrow and reduce subsequently.
The rain-friendly monsoon trough over India is being sustained by embedded cyclonic circulations over northern parts of Haryana and neighbourhood as well as over East Uttar Pradesh and adjoining Bihar.
Bay to remain 'rough'
In a detailed forecast for today, the IMD said heavy to very heavy rain with extremely heavy rain is likely to lash Odisha. It will be heavy to very heavy rain over Jharkhand. 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' would 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 these areas.
Outlook for tomorrow said heavy to very heavy rain is likely over Odisha, while it would be heavy over Assam, Meghalaya, Nagaland, Manipur, Mizoram, Tripura, plains of Bengal, Jharkhand, Uttarakhand, West Madhya Pradesh and Chhattisgarh.
The sea may in 'rough' to 'very rough' over the North Bay off Odisha, Bengal and Bangladesh coasts. Fishermen are advised not to venture into these areas.
Quiet over peninsula
As the cross-equatorial flow, which brings in the monsoon winds across from the Southern Hemisphere into the Arabian Sea and the Bay of Bengal continues to remain weak, rainfall activity over Peninsular India could remain subdued during the next four 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 Comorin area across interior Tamil Nadu persists. 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 Peninsular India.
The Met subdivisions of Rayalaseema (-46 per cent) and North Interior Karnataka (-22 per cent) as well as the Lakshadweep Islands (-44 per cent) could witness the prevailing rain deficits grow further during this period.
To the North, Haryana, Chandigarh ad Delhi and West Rajasthan (-21 per cent each) have fallen into deficit; Jharkhand improved it to -21 per cent; while Saurashtra & Kutch's worsened to -25 per cent.