North-east monsoon could extend into the New Year

From October 1 to December 20, Tamil Nadu recorded cumulative rainfall of 450.7 mm against the normal rainfall of 424.5 mm.

Chennai: North-east monsoon (NEM), the lifeline monsoon of Tamil Nadu, might extend into 2024 instead of withdrawing in the last week of December, bringing more rains to several parts of the state, including Chennai and its neighbouring districts.

Though several parts of the state were ravaged due to unprecedented excessive rainfall, the Indian Meteorological Department (IMD) has categorised the monsoon as “normal” as the cumulative rainfall in Tamil Nadu registered an increase of just 6 per cent.

From October 1 to December 20, Tamil Nadu recorded cumulative rainfall of 450.7 mm (45 cm) against the normal rainfall of 424.5 mm (42 cm). “This is an increase of 6 per cent,” the IMD said.

Of the 38 districts, five districts came under large excess category (over 60 per cent or more rainfall), while eight districts fell under excess category (over 20 to 59 per cent more rainfall), 12 districts (normal category) and 15 districts (deficient category) between October 1 and December 20.

While NEM set over Tamil Nadu in the last week of October, the monsoon became intense in November and in the first week of December due to the influence of Cyclone Michaung in Chennai and its neighbouring districts which received extremely heavy rainfall for two days. Perungudi in Chennai recorded about 70 cm of rainfall in just 36 hours.

Weeks later, Thoothukudi and Tirunelveli were battered by extremely heavy rainfall with Kayalpattinam recorded a whooping 116 cm rainfall in 48 hours. The IMD data says Tirunelvei recorded 151 per cent rainfall more than normal in the week ending December 20, while it is 92 per cent more in Thoothukudi for the same period.

“NEM is extending into January. Last days of the year and the 1st week of January,” independent weather blogger Pradeep John said, adding that the trough interaction between easterlies and westerlies might result in rains if the interaction happens in sea.

“If the interaction happens in landmass, then there will be heavy rains in some places which will be associated with thunder and lightning,” John further said.

However, another weather blogger K Srikanth, said while the westerly and easterly interaction could bring rains, it would be difficult to say whether monsoon conditions would prevail.

"There'll be rains in the last few days of 2023 and the first week of 2024, but I don’t think it is the NEM extending. I believe NEM is almost over and I don’t see any active monsoon conditions,” Srikanth added.