Following a brief respite, Tamil Nadu and Puducherry are set to receive rain over the next 24 hours.
Heavy rainfall is likely to occur at isolated places over Mayiladuthurai, Nagapattinam, Tiruvarur, Thanjavur and Pudukottai districts, the Regional Meteorological Centre said on Saturday.
For Chennai, the sky is expected to be partly cloudy and light rain is likely to occur in a few areas during the next 24 hours.
The bulletin issued by the weather office located in Chennai stated that light to moderate rain is likely to occur at a few places over coastal Tamil Nadu and at isolated places in interior Tamil Nadu, Puducherry and Karaikal.
It also predicted thunderstorms and lightning at one or two places.
In an X post, Tamil Nadu weatherman Pradeep John stated that the active phase of the Northeast Monsoon is set to begin for Tamil Nadu, attributing it to the Equatorial Rossby (ER) Wave.
"This is happening without the support of the King MJO (Madden-Julian Oscillation), which remains stuck over the Pacific Ocean. It is extremely rare to see such an active monsoon phase without MJO. We are about to witness one over the next two weeks. IMD too attributes the upcoming rains and the possible next system to the influence of the Equatorial Rossby (ER) Wave," he said.
Madden-Julian Oscillation is the major component of the intra-seasonal variability in the tropical atmosphere. It consists of large-scale coupled patterns in atmospheric circulation and deep convection.
It is often nicknamed King MJO by weather enthusiasts to describe its significant impact, as its movement is linked to the development of active rainy periods.
The North East Monsoon, which officially set in on October 16, has brought 30 cm of rain to date to Tamil Nadu. An Upper Air Circulation that stayed over the Southwest and adjoining Southeast Bay of Bengal now exist over South Sri Lanka and adjoining Southwest Bay of Bengal.
The Met department had advised fishermen not to venture into the sea between Saturday and Sunday (November 15 and 16, 2025). Squally weather with wind speed reaching 35 km ph to 45 km ph, ghusting to 55 km ph is to prevail along and off the Tamil Nadu coast, over the Gulf of Mannar and the Comorin area.