Cloud cover keeps daytime temperatures down, humidity up

Chennai: The city may not receive heavy rainfall on Sunday, but daytime temperatures are likely to remain under check as clouds associated with an atmospheric disturbance over the west coast reduce the amount of solar radiation reaching the surface.The IMD has forecast light rainfall over the city. Private forecasters said while daytime temperatures may remain pleasant for the next two to three days, night temperatures and humidity are likely to rise, making the weather muggy.“On Sunday, the city and the suburbs may experience partly cloudy skies with a maximum temperature of 36-37°C and a minimum of 27-28°C,” an IMD bulletin said.On Saturday, persistent cloud cover brought daytime temperatures down to 32.2°C in Nungambakkam and 32.4°C in Meenambakkam, around 4.4°C and 4.3°C below normal.

However, relative humidity remained high at 59-77%.Meteorologists said the cloud cover resulted from moisture transported eastwards by strong southwesterly monsoon winds. A trough, an elongated region of relatively low atmospheric pressure extending from Maharashtra to Karnataka, is triggering widespread rainfall over the west coast and interior Karnataka. The strengthened monsoon flow is carrying some of this moisture across the Western Ghats towards Tamil Nadu, producing extensive cloud cover over coastal districts even without significant rainfall.

“Normally, much of the moisture gets depleted over the Nilgiris. But the southwesterly winds are currently strong enough to push moisture towards the east coast. Daytime temperatures may remain slightly below normal for the next couple of days, though we do not expect any significant rainfall over Chennai,” said Mahesh Palawat, chief meteorologist, Skymet Weather.Meteorologists said the increased moisture and cloud cover may keep daytime temperatures lower but also raise humidity. On Saturday, Nungambakkam and Meenambakkam recorded 28.4 deg C and 29.1 degC just before sunrise, around 1.1 and 2.2 degrees above normal. The rise in night temperature is due to clouds and water vapour reducing the escape of heat from the surface, keeping minimum temperatures above normal and making the weather feel warmer.