The low-pressure area over south-east Bay of Bengal has intensified one round into a well-marked ‘low’ on Monday.
This happened after typhoon Haiyan ended its destructive run over the Philippines, Vietnam and parts of south-west China on Monday.
India Met Department expects the ‘low’ in the Bay to intensify further into a depression, the equivalent of a minimal tropical storm, by Tuesday.
Sea-surface temperatures over south-east and adjoining south-central Bay of Bengal are close to 30 degrees Celsius, which provides it the perfect environment for intensification.
But the warmth tapers off over the south-west Bay which the depression will spin its way into in due course, and which abuts the Tamil Nadu coast where it will make a landfall by the weekend.
The moot question is whether the depression will strengthen into a deep depression (next to being called a tropical cyclone) before it enters Tamil Nadu.
On Monday, no weather model seemed to be indicating such an eventuality though most saw moderate to heavy rain lashing the north Tamil Nadu-south Andhra Pradesh coast.
India Met Department expected the rainfall activity to increase over Tamil Nadu and Andhra Pradesh coasts from the weekend.
US forecasters saw another likely week of moderate rainfall for most of Tamil Nadu, Kerala and parts of Karnataka next week.
Meanwhile in the North, the colder minimum temperatures below 10 degree Celsius extended to more parts of western Himalayas and pockets of Punjab, Haryana and north Rajasthan.
Minimum temperatures are below normal by 2-3 degree Celsius over many parts of northwest and northeast India, Saurashtra, Kutch, Odisha, east Madhya Pradesh, north Andhra Pradesh and north Karnataka.
Najibabad in Uttar Pradesh retained the status of being the coldest place (7.6 degree Celsius) in the plains for a second day on Monday.