Warmer days likely in February; surplus rain, chilly mornings mark January

January ended on a surplus note in the State as the month was interspersed with multiple rain spells and the delayed withdrawal of Northeast monsoon. The Regional Meteorological Centre (RMC) has forecast that light rainfall may occur in coastal and Western Ghats districts until February 6.

Officials of the RMC said an upper-air cyclonic circulation moving over the Bay of Bengal is likely to bring mild rainfall in coastal and Western Ghats districts spread over the next six days. While there is a possibility of fog conditions in northern districts, such as Krishnagiri, Ranipet, and Tiruvallur, until February 4, districts like Erode, Namakkal, and Karur may experience mist cover.

In its outlook for February, the India Meteorological Department has predicted the probability of below normal rainfall in most parts of the State. Chilly weather may be restricted to a few days as the minimum temperature is likely to be normal or above normal in most parts of the State. Similarly, the State may experience an above-average maximum temperature in February.

This January, Tamil Nadu recorded total rainfall of 33.1 mm against its monthly average of 12.2 mm. Most districts, including Chennai, Tenkasi, Thanjavur, Nilgiris and Namakkal, had received more than double their normal share of January rainfall. Residents of various places like Chennai also experienced chill weather on many days of the month.

B. Amudha, Head (Additional in-charge), RMC, said the State experienced three rainfall spells interspersed with dry days this January that lifted the month’s total rainfall. The rainfall was due to Easterly wave activity and two upper-air cyclonic circulations.

On cold January weather, she said, though official weather observations showed near-normal temperatures, many people felt chilly. This is due to the difference in measurements taken under a protected environment and those experienced in direct exposure to the open environment.

For instance, Nungambakkam recorded a temperature below 20 degrees Celsius on January 18, and Meenambakkam recorded temperatures below 20 degrees Celsius on three days. Nungambakkam recorded the decade’s fourth-lowest minimum temperature of 19.7 degrees Celsius, and Meenambakkam recorded 19 degrees Celsius on January 18. There have been years in the past when the minimum temperature dipped lower than this in January.

Residents experienced nippy, hill station-like weather because the temperature hovered between 22 and 23 degrees Celsius till 8 a.m. The real-time feel temperature can often be lower than observed minimum temperature readings, and it may vary within a radius of a few km.

Clear skies, calm winds, relative humidity and the extent of radiation cooling determine weather in a particular area. Microclimatic variations may also influence chill weather. Areas with more water bodies in the neighbourhood, like near Chennai Airport, are also prone to mist formation, Ms. Amudha said.