The northeast monsoon is likely to arrive in the southern peninsula — coastal Andhra Pradesh, Rayalaseema, Tamil Nadu, Kerala and south interior Karnataka — within the next 24 to 48 hours. While it brings heavy rainfall in these regions, its deficiency may lead to drought or drought-like conditions in the southern parts of the country.

According to officials, the weather conditions are favourable for the arrival of northeast monsoon and withdrawal of southwest monsoon. The arrival of northeast monsoon was halted by Cyclone Titli in the Bay of Bengal. The northeast monsoon that spans from October to December mainly affects the five regions in the southern peninsula.

Officials said unlike southwest monsoon, there is no official onset date for northeast monsoon, which sets in one go over the region, while the former sets in place by place.

According to private weather forecaster Skymet, the withdrawal of southwest monsoon 2018 commenced very late on September 28. “In fact, southwest monsoon started retreating at a rapid pace and at that point it seemed that this would be the quickest withdrawal of monsoon in the last few years,” the Skymet said.

The Skymet said monsoon had withdrawn from entire northwest, east and central India within a week. Not only this, conditions were looking favourable for the early onset of northeast monsoon during the second week of October itself.

Meanwhile, the India Meteorological Department has expressed hope of normal northeast monsoon, this year.

The IMD has cited neutral El Nino conditions in the Pacific and the neutral Indian Ocean Dipole (IOD), both of which have a bearing on rainfall in the Indian subcontinent, as supporting evidence for the outlook.

 “While large parts of India depend on summer rain, the northeast monsoon is still crucial for several southern States which receive about 30 per cent of their annual rainfall during this season, with the exception of Tamil Nadu, which receives nearly half its rains during these months,” IMD officials said.

However, onset of northeast monsoon is never attempted before the withdrawal of southwest monsoon from the entire country. Normally, the season sets in around October 20, with an error margin of +/-5 days.

While Kerala and South Interior Karnataka record around 20 per cent of its annual rainfall during the season, rest of the sub-divisions witness around 50 per cent of its annual rainfall, with parts of coastal Tamil Nadu even recording 70 per cent of rainfall. As the season advances the rainfall is mainly in the coastal districts with the interior districts getting less rain.

Rainfall pattern would also undergo some changes as the rainfall that usually occurs during afternoon and late evening, would now be witnessed during night and early morning hours. However, if there is any system, we can expect rain all along the day.

This year, the country received 91 per cent of Long Period Average (LPA) rainfall, which falls under the “below normal” category. The east and northeast India, including Bihar, West Bengal and Northeastern States witnessed maximum rainfall deficiency. On the other hand, Kerala witnessed unprecedented rainfall and subsequent flooding.