PATNA: Meteorologists say winter season will officially commence from Tuesday (December 1). They also say the three-month crisp weather will be colder this time as minimum temperature is likely to be few notches lower than the corresponding normal.
Sanjay Kumar of Patna Meteorological Centre told TOI on Monday that ‘moderate’ La Nina weather phenomenon is responsible for the expected plunge in temperature. “The minimum temperature remains comparatively lower under the influence of La Nina weather phenomenon, which leads to lower sea surface temperature, particularly in the Mediterranean Pacific Ocean. Accordingly, north-west India, northern plains and parts of eastern India, including Bihar, are likely to witness lower temperature this year,” he said.
As far as the prevailing weather condition is concerned, the lowest minimum temperature in Bihar was recorded 9.2 degrees C at Gaya. The minimum temperature at Patna, on the other hand, was 11 degrees C, which was one notch lower than the corresponding normal for the day.
Amit Sinha, an officer at Patna Meteorological Centre, said weather is getting colder in majority parts of north Bihar owing to snowfall and cold wave. “Weather is likely to remain colder in Bihar under the influence of cold and dry northwesterly winds. The wind speed increased on Monday, which will lead to further plunge in minimum temperature,” he said, adding that foggy conditions can be witnessed near water bodies, including rivers and ponds.
India Meteorological Department (IMD) on Sunday issued seasonal forecast for December to February period. It stated that below normal minimum temperatures are likely over most subdivisions of north, northwest, central and few subdivisions over east India.
“As per the season forecast, the temperature in Bihar will also be comparatively lower. Besides, the frequency of western disturbances and their influence over weather in Bihar is likely to be higher this year, which may further intensify winter conditions,” Sanjay said.
The western disturbances are low-pressure area or extra-tropical storms originating from Mediterranean Sea, Red Sea and Caspian Sea, which cause snow and winter rainfalls in northwestern Indian subcontinent. Apart from rain, the western disturbances are usually followed by sudden plunge in temperature along with foggy conditions owing to the remnant moisture in the atmosphere.
The influence of western disturbances is at times followed by cold wave. A cold wave condition is declared at a place when the normal minimum temperature is 10 degrees C or above and departure from normal is 4.5-6.5 degrees C for two consecutive days.
According to sources, there was no spell of cold wave in the winter last year, but weathermen claimed that this time few such spells will be witnessed over the next two months.
“While we are expecting few western disturbances to influence the weather conditions in northern plains this winter, the departure of the minimum temperature from the corresponding normal is also likely to lead to few spells of cold wave,” Sanjay said.