The rainfall activity over most parts of the country may begin to lose intensity starting September 19, according to an extended range forecast by India Met Department (IMD).
However, above normal rainfall is forecast during the week along the West Coast, Karnataka, Tamil Nadu and Coastal Andhra Pradesh. It is very likely to be normal to below normal over the remaining parts of the country.
Monsoon withdrawal
This would mean that the withdrawal of monsoon may gather pace from North, North-West and East India from next week, even as the South Peninsula offers some resistance.
Meanwhile, Thursday saw heavy rainfall being reported from East Madhya Pradesh, Chhattisgarh and Jharkhand, even as a causative low-pressure showed no signs of weakening this (Friday) morning.
The ‘low’ lies over North-East Madhya Pradesh and adjoining South-East Uttar Pradesh, and makes for a conducive alignment for not just the monsoon trough, but also a secondary trough.
The troughs receive moisture from the Bay of Bengal and the Arabian Sea and determine the spread of rainfall over the region under their footprint as evident from the pattern available concurrently.
The monsoon trough passed through Anupgarh, Alwar, Gwalior, centre of the ‘low’ over North-East Madhya Pradesh and adjoining South-East Uttar Pradesh, Daltonganj, Berhampore and dips into the North-East Bay.
The secondary trough extends from South Gujarat to North Bangladesh and runs from Kutch to the hills of Bengal within Indian territory, and across South-West Madhya Pradesh, the ‘low’ and Southern Bihar.
Widespread rainfall
Two other monsoon-friendly features are the cyclonic circulations over North-East Arabian Sea and adjoining Saurashtra and Kutch persists and over North Kerala coast and neighbourhood.
The IMD sees these systems bringing fairly widespread to widespread rainfall with heavy to very heavy falls over Madhya Pradesh during the next three days. It will be heavy over Odisha, Gujarat, Assam, Meghalaya and Arunachal Pradesh until tomorrow (Saturday).
Detailed forecast for rest of today (Friday) said that heavy to very heavy rainfall is likely over Madhya Pradesh while it would be heavy over Uttarakhand, Uttar Pradesh, East Rajasthan, Bihar, hills of Bengal, Sikkim, Odisha, Arunachal Pradesh, Assam, Meghalaya, Gujarat, Konkan, Goa, Tamil Nadu and Puducherry.
As for tomorrow (Saturday), heavy to very heavy rainfall is likely over West Madhya Pradesh and heavy over East Uttar Pradesh, East Rajasthan, East Madhya Pradesh and the Andaman and Nicobar Islands.
Strong winds, with speeds reaching up to 50 km/hr, have been forecast to prevail on both days over the West-Central and South-West Arabian Sea. Fishermen are advised not to venture into these areas.
The extended forecast valid from September 18 to 20 said that fairly widespread to widespread rainfall with isolated heavy falls is likely to occur over North-East India and parts of East and Central India.
Scattered to fairly widespread rainfall with isolated heavy may lash the Northern parts of the West Coast while it would be isolated to scattered over rest of the country outside North-West India it would be isolated.
Large surplus
Meanwhile, the monsoon was confined to over the central parts of the country with above normal rainfall — 142 per cent over Central India and 16 per cent over South Peninsula — during the week between September 5 to 11.
During this week, rainfall over the country as a whole was 38 per cent above the long-period average (LPA).
Rainfall for the country as whole during the season thus far (June 1 to September 11) is three per cent above the LPA, with East and North-East India alone turning up a deficit among the four main geographic regions. It was 21 per cent above the LPA over Central India, 10 per cent above the LPA over South Peninsula; but minus 9 per cent, considered within the normal deviation from normal, over North-West India.
Forecast for the ongoing week (September 12 to 18) said that fairly widespread to widespread rainfall with isolated heavy to very heavy falls is likely over Madhya Pradesh while it would be fairly widespread with isolated heavy falls over East Uttar Pradesh during most days of the week.
Fairly widespread to widespread rainfall may occur over East India (Odisha, plains of Bengal, Bihar Jharkhand) during the week with isolated heavy falls on Thursday and Friday.
Cumulatively, above normal rainfall is forecast during the week for Gujarat, the West Coast (except Kerala), East Rajasthan, East Uttar Pradesh, Madhya Pradesh, Bihar, hills of Bengal, Sikkim and Arunachal Pradesh.
It is very likely to be normal to below normal over remaining parts of the country.