A well marked low pressure area lay over Bay of Bengal and it is very likely to concentrate into a depression and bring rains in Tamil Nadu, Puducherry, Kerala and south coastal Andhra Pradesh till December 3, the India Meteorological Department said on Sunday.
The low pressure area on Saturday over south Andaman sea and adjoining areas of southeast Bay of Bengal has organised into a well marked low pressure area, the Regional Meteorological Centre here said in a bulletin.
"It is very likely to concentrate into a depression during next 36 hours and likely to intensify further thereafter. It is likely to move west-northwestwards and reach near south Tamil Nadu coast around December 2."
Under the influence of the system, light to moderate rainfall or thundershower is likely over Tamil Nadu, Puducherry and Karaikal till December 3.
The showers, in such regions, starting with isolated places, could extend to many areas and then spread to most places during the next four days, the bulletin said.
The IMD tweeted,"Scattered to widespread rainfall activity very likely over Tamil Nadu, Puducherry & Karaikal, Kerala & Mahe, Lakshadweep, south coastal Andhra Pradesh and south Rayalaseema during 01st-03rd December, 2020."
Also, the department said, "Isolated heavy to very heavy rainfall with moderate thunderstorm & lightning very likely over Tamil Nadu, Puducherry & Karaikal during December 1-3 and isolated extremely rainfall likely over south Tamil Nadu and south Kerala on 02nd December 2020."
The expected rainfall is due to the well marked low pressure area, it said.
In Kerala, a red alert has been sounded for Idukki district on Wednesday and fishermen restrained from putting out to sea from the midnight of November 30.
An Orange alert has been issued for Thiruvananthapuram, Kollam and Pathanamthitta districts on December 2 anda yellow alert for Alappuzha, Kottayam and Ernakulam districts on the same day.
Red alert indicates heavy to very heavy rainfall of over 20 cm in 24 hours,an Orange alert (6 cm to 20 cm) and yellow alert (6-11 cm).