September, October and November may witness largely "climatological" conditions over India - which means the least possibility of deviation from historically observed weather pattern.
The usual pattern is for monsoon to start retreating from extreme west Rajasthan from September 1. It will progressively retreat from more areas to exit the landmass entirely by the end of September.
Withdrawal would technically mean the end of rains, but the north-west region has been known to receive stray showers from passing western disturbances even during September.
Occasionally, the withdrawal process has even been forced to call a halt due to intervening rains over northwest and even central India.
Given this, the process needs to be watched for any late-season rains that would add to crucial soil moisture for the rabi crop.
The International Research Institute for Climate Prediction at Columbia University sees an enhanced possibility of a reasonably good north-east monsoon, especially from November. But the gains may mostly accrue for the south peninsula.
According to the Busan, South Korea-based Asia-Pacific Climate Centre (APCC), the west coast, south peninsula and the east coast may see below- or near-normal rainfall till October, along with above-normal temperatures.
During October, probability of near-normal rains is indicated for north, northwest and east India. The south peninsula and the southeast coast will sit out of this regime.
But there is a chance that the rainfall signals over India may be near-normal in November, the APCC added.
Normal Winter
Collectively, early signals suggest normal winter precipitation regime varyingly for northwest and east India. This is strikingly in contrast with winter of the previous year when rains failed the region for the most part.
Meanwhile, in a monsoon status update on Friday, the Indian Met Department (IMD) said there has been significant improvement in monsoon activity over the south peninsula, northwest and northeast India during the week ending August 19 (Wednesday).
The Gangetic plains, foothills of the Himalayas, Assam, Meghalaya, Arunachal Pradesh and the south peninsula excluding the west coast received excess rainfall from a partial revival of the monsoon. But the rains were subdued over central India while being scanty over Maharashtra, Gujarat and west Rajasthan.
The monsoon trough may remain close to the foothills of the Himalayas till Sunday and return to its normal position thereafter to signal further recovery in rainfall.
Fairly widespread rainfall with isolated heavy to very heavy falls is likely along the foothills of the Himalayas and the Northeastern Sates till Sunday and decrease thereafter.
Bay Whirl
A cyclonic circulation is likely to develop over northwest Bay of Bengal around Monday and may move westward across Orissa and Chhattisgarh to signal the revival of monsoon rains over these regions.
The IMD too has since joined the watch for monsoon to improve over Orissa, south Chhattisgarh and north Andhra Pradesh from August 24 (Monday) and north Karnataka, Maharashtra and adjoining Madhya Pradesh and Gujarat two days hence, with fairly widespread rainfall and isolated heavy to very heavy falls.
Gradual strengthening of lower-level westerlies is likely over the south and central Arabian Sea along with likely development of an offshore trough along the west coast.
Considering the large-scale features, the Madden-Julian Oscillation index is likely to be favourable from the second half of the week for enhanced rainfall activity, especially in central and peninsular India, the IMD update added.
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