The extended NE monsoon also triggered copious rainfall so far this January over the State
| Photo Credit: L. Balachandar
After nearly 100 days since its onset and bountiful rainfall, Northeast monsoon has finally retreated from Tamil Nadu on Monday. This is one of the rare years when the monsoon prolonged till January end.
The extended NE monsoon also triggered copious rainfall so far this January over the State. With largely dry weather prevailing for the past few days, the Regional Meteorological Centre, Chennai, announced that NE monsoon ceased over the south peninsular region on Monday.
The monsoon, which set in around October 15, 2024, was one of the unusually prolonged seasons and spilled over to January this year. Tamil Nadu received nearly 58.9 cm of rainfall against its average share of 44.3 cm of rainfall during the core October and December monsoon months. Back to back weather systems had caused widespread rainfall during the season.
P.Senthamarai Kannan, Director, Area Cyclone Warning Centre, RMC said recurring minor weather systems over TN led to prolonged NE monsoon beyond its usual timeline. Though the season was interspersed with gaps in rainfall, the movement of weather systems kept the monsoon active.
The State previously had a delayed monsoon withdrawal after mid-January on January 22, 2022. Normally, the monsoon withdrawal would occur between December 26 and December 30 every year. The season has a standard deviation of 13-14 days, noted officials.
Citing his papers published by IMD, Y.E.A.Raj, former deputy director general of meteorology, Chennai, said the NE monsoon spilling into the period of January 21-31 was rare. The State experienced the most delayed monsoon of 19933-34 on January 28. This year too would be one of the rare occasions when the monsoon extended till January-end. Pointing out that the previous year’s season spilled over to the next calendar year during one-third of the years since 1901.
Monsoon had retreated from the State during the first 10 days of January during 28 years since 1901. This weather phenomenon of extended monsoon has become more frequent since 2011, he added.
Officials noted that unlike Southwest monsoon, NE monsoon also called retreating monsoon, did not have a dramatic change in weather parameters like reversal in wind flow pattern during withdrawal. Dip in rainfall was one of the major criteria taken into account for monsoon retreat.
Meanwhile, the State may have another rain spell from January 30 particularly over south Tamil Nadu. The RMC has predicted rainfall could be heavy in some places of south TN like Tenkasi, Thoothukudi, Tirunelveli and Kanniyakumari districs till February 1. A few places over north TN too would receive rainfall. A cyclonic circulation over southwest Bay of Bengal would influence the return of wet weather towards the month-end. Isolated pockets in the State may have mist/haze cover during early morning hours on Tuesday.
Published – January 28, 2025 12:50 am IST