Humidity levels are climbing in Mumbai while light rain is being reported from Goa as the Konkan coast awaited a formal declaration of the monsoon.
A couple of thunderstorms are being forecast for the day in Mumbai where relative humidity levels have reached 79 per cent.
Goa is experiencing a much higher humidity of 99 per cent from where light rain has been reported in the morning.
Relative humidity is the ratio of the current absolute humidity to the highest possible absolute humidity (which depends on the current air temperature).
A reading of 100 per cent relative humidity means that the air is totally saturated with water vapour and cannot hold any more, creating the possibility of rain.
During a monsoon, moisture-laden winds from the sea blow into the Indian landmass which represents a massive area of low pressure from rising air due to extreme heating of land.
COOLING OF MOISTURE
Moisture also gets lifted by orography of land, or mountains and other raised geographical features.
This is best evidenced in the heavy precipitation along the windward areas of Western Ghats along the west coast and the Himalayas to the east.
Here, the moisture thus lifted gets cooled (temperature and pressure get reduced with height in the atmosphere) in the higher levels and is readily precipitated.
India Met Department has said in a late night bulletin that the monsoon has entered into parts of interior Karnataka, most of Tamil Nadu and parts of west-central and northwest Bay of Bengal.
MAKES PROGRESS
The northern limit of the monsoon passed through Ratnagiri, Chitradurga, Bangalore and Chennai in the peninsula and Cooch Behar and Gangtok in the east of the country.
Conditions are favourable for the monsoon to enter the Konkan, more parts of interior Karnataka and south Madhya Maharashtra during next two days.
Conditions are also becoming favourable for it to enter Gangetic West Bengal, Odisha, Jharkhand and Bihar during the next four days.