RAIN IN SIGHT

Brace for a comfortable weekend after the 40-plus mid-week. Saturday and Sunday would be cloudy.

Expect slight showers. Also, thunderstorm is likely at one or two places in the central Bihar region, in which Patna is located.

The Met office is apprehending more disturbed weather in the north and eastern parts of the state over the next two days. The forecast said it would rain in the northern and eastern districts in the next two days and few places might encounter thunder squall.

A thunder squall on Tuesday night had wrecked havoc in the northeastern districts, leading to death of more than 50 people and large-scale devastation of property and standing crops.

Weathermen attributed the fluctuation of weather in the city - from the 40-plus temperature to balmy conditions - to frequent change in the wind direction.

"While easterlies dominated for the past two days, westerlies have now taken over as the dominant wind," Patna Met director Ashish Sen told The Telegraph.

Easterlies lead to incursion of moisture. When dry westerlies start blowing, it pushes the moist wind upwards, leading to cloud formation.

It happens so because moist winds are lighter than the dry wind. This phenomenon is density-dependent.

The density of water vapour is less than air. Hence, moist wind is lighter than the dry wind.

Sen said the formation of cloud leads to rains at a few places and when this cloud becomes thick and take the form of cumulonimbus clouds, which have vertical extent up to 12km sometimes, thunderstorm occurs.

The weathermen said the highest temperature would one to two notches below the normal temperature - 37°C - at this time of the year. Cloud cover, however, leads to a little increase in the minimum temperature because the heat radiated by the earth surface gets trapped in the lower level of the atmosphere, increasing the minimum temperature.

While most of the city residents appeared happy over the likely cooler condition in the in the weekend, a few looked apprehensive. "I have a family function slotted for Sunday and if it rains or there is a thunderstorm, my function would definitely be disturbed," said Kundan Kumar, a resident of the Jaipal Singh Road locality in west Patna.

The likely weather condition is also a bad news for farmers who are planning to harvest the standing crop.

"At least a week's duration of dry and sunny weather would be ideal for harvesting. Cloudy condition accompanied by wind does not allow the standing crop to dry up properly. Possibility of rain is another problem as it would add moisture to the crop," agriculture expert Anil Kumar Jha said.

He said rain softens the soil and gusty winds lead to flattening of crop, which increases the chances of grains rotting after coming in contact with the wet surface.

But for getting a dry spell, farmers would have to wait for now. Skies are likely to be clear from Monday.

It would lead to increase in the day temperature, which would near the 40°C-mark from April 28, the Met director said.