A low pressure area over Southeast Bay of Bengal (BoB) has intensified to become well marked low(WML) pressure. Weather system has also moved west-northwest and lies over South - Central BoB. WML is centred around 87 degrees East and 10 degrees North today morning, about 700 km southeast of Chennai.
WML is presently having wind field of the order of 35-40 kmph around the centre. Sea surface temperature is moderately warm and limited to 28-29 degree Celsius. Under such conditions, WML is likely to concentrate in to a depression by late tonight or early tomorrow. It may further escalate to a deep depression but unlikely to become a storm. It is moving west-northwest and is expected to come over southwest BoB , 300 km off the coastline of Tamil Nadu, by 20th Nov.
The peripheral clouds and squally winds of the system will reach the coast by tomorrow. However, noticeable weather activity will commence on 20th Nov, affecting coastal Tamil Nadu and South Coastal Andhra Pradesh. Proximity of the coastline will possibly weaken the system after 20th Nov. Tamil Nadu and Andhra Pradesh can expect spike in weather activity between 20th and 22nd Nov. Later, the weakened low pressure will also extend the rainfall belt to Rayalaseema, South Interior Karnataka and Kerala.
Low pressure is likely to move westward and cross over to the Arabian Sea on 24th Nov. It will continue to affect weather over South Peninsula on 24th & 25th Nov. Weather activity will reduce substantially on 26th Nov when the cyclonic circulation of low pressure shifts far over South-Central Arabian Sea.
While this weather system crosses over to Arabian Sea on 24th Nov, another low pressure is expected to pop up over North Andaman Sea. This low pressure will travel from Gulf of Thailand to enter Bay of Bengal, cutting across Arakan Coast of Myanmar. This system may not travel towards Tamil Nadu and Andhra Pradesh. Instead, it may cut short the sea travel and turn towards Myanmar and Bangladesh.