Brace for a chilly Christmas on Thursday.

The Met office on Tuesday issued a cold wave alert in the state for the next 24 hours, suggesting a nippy Christmas Eve. Revellers might shiver on the Christmas Day as well because weathermen have ruled out any respite from the biting cold till the weekend. Based on the prevailing conditions, meteorologists expect the minimum temperature to hover around 6-7°C and the maximum around 17-18°C this week.

Children would be happy, though. Santa Claus, used to sub-zero temperatures, would bring them gifts.

Cold wave conditions prevailed in the city and Gaya even on Tuesday. Chilly breeze from the Himalayan foothills pushed the mercury column in Patna to the season's lowest - six-degree mark on Monday. The minimum temperature on Tuesday was 6.5°C.

The minimum temperature in Gaya was 5.7°C and 9.8°C on Monday and Tuesday, respectively.

The two cities are reeling from cold because of the western disturbance in Himalayan foothills and its induced cyclonic circulation in the region. Chilly westerly winds from the Himalayan region are pushing the night temperature down. The cyclonic circulation is leading to moisture incursion and the subsequent fog cover in the morning.

The maximum temperature is remaining low in the absence of sunshine, triggering day cold condition.

R.K. Giri of Patna Meteorological Centre said: 'The western disturbance has weakened but the region is still under its impact because of heavy snowfall in the Himalayan foothills. The induced cyclonic circulation has led to high moisture incursion in the atmosphere, which is augmenting the formation of fog-cover. The prevailing condition is likely to sustain at least till the end of this week.'

Flight and train operations were disrupted because of the foggy condition on Tuesday. The first flight landed at Patna airport around 2.45pm, leading to cancellation of Jet Airways' Calcutta-bound flight (9W 2685) and delay of several others.

Fog has been delaying trains to and from Patna Junction as well.

On an average, around a dozen trains are getting delayed daily over the past 15 days. Most trains coming from Delhi and other parts of northern India have been running late by several hours because of fog. Hundreds of passengers can be seen sleeping on platforms at Patna Junction because of trains running late.

There was some respite from the chilly breeze on foggy Tuesday, though. The average wind speed in Patna came down from 10-12kmph on Sunday and Monday to 5 to7kmph on Tuesday.

Weathermen claimed that extended spells of chilly conditions were likely to prevail in the state till mid-January.

'Heavy snowfall in Himachal Pradesh, Uttarakhand, and Jammu and Kashmir between December 20 and mid-January because of western disturbances lead to extended spell of cold wave in Bihar as well. That is why the winter remains at its peak in Bihar around this time of the year,' said Giri.

Weathermen are expecting light showers in the state around December 30. 'A low-pressure area is likely to be formed in Bay of Bengal around December 30, which can lead to light rainfall in some parts of Bihar as well,' said Giri.

TAKE CARE

Winter is the season of fun and one needs to be fit to enjoy it to the hilt. A few healthy tips:

Put on woollens while going out

Use lukewarm water for bath because fluctuating temperature could have bad effect on health

People having high blood pressure, respiratory (such as asthma) and cardiac diseases should avoid going for morning and evening walks. Exposure to extreme cold condition can lead to increase in blood pressure, triggering brain haemorrhage

Elderly people should go for the pneumococcal vaccine to shield themselves from pneumonia

If you catch cold, cover your mouth while sneezing 

Drink as much as water you can because body requires it even in winter 

Avoid fruit juice, go for soup

Source: Dr V.P. Sinha, physician, Patna Medical College and Hospital, and Dr S.C. Jha, cardio-thoracic surgeon, Patna Medical College and Hospital