Brace for cold wave ahead

BRRR: People walk through fog on a chilly winter morning in Gaya on Wednesday. Picture by Suman

Patna: There is no respite yet from the below normal temperatures in Patna and other parts of the state as the city stares at a cold wave in the next two days.

It is called a cold wave condition when the minimum temperature is 4.5-6.4 degrees C below normal and the normal minimum for the given day is 10 degree C or less. Meteorologists also declare a cold wave condition if the observed minimum temperature for a given day is 4 degrees C or less.

"Going by the current trend, there is every possibility of cold wave at a few places, including Patna in Bihar," Patna Met office scientist Anand Shankar said. On Wednesday, Patna recorded a minimum of 7.1 degrees C, two notches below normal. Several other places in the state recorded below-normal minimum temperature, coldest being Bhagalpur and Darbhanga, which recorded a minimum of 5.6 degrees C each. Gaya was marginally better but still very cold at 5.8 degrees C.

Several other places - Purnea (7.1 degrees C), Muzaffarpur (7.1 degrees C) and Chhapra (6.5 degrees C) - recorded below normal minimum temperatures.

Giving reasons for the drop in minimum temperatures, Met scientist Anand Shankar said thinning of fog cover was causing it.

Patna is likely to witness shallow to dense fog cover in the morning hours in the coming 2-3 days. Fog cover is said to be dense when visibility is in the range of 50-500m and moderate when in the range of 800-1,000m.

The fog cover is thinning because of strong westerlies blowing at 6-8kmph for the past 2-3 days. The westerlies are likely to gain in strength in the coming 2-3 days. Westerlies also lead to drop in humidity level, increasing chances of reduction in dense fog.

The strong wind also leads to the cold factor, called wind-chill factor in meteorological parlance, and is defined as the perceived decrease in air temperature felt by the body because of air flow.

Expressing concern at the prevailing weather condition, Ashiana Nagar resident Manorama Prasad said: "My daughter's school is scheduled to open on January 8 after the winter break. I hope the local administration takes a call and extends the holidays, as sending children outside in the prevailing condition does not look safe." Manorama's daughter is a Class II student at the city's Don Bosco primary school.


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