Bengaluru, May 25 (IANS): Amid scorching summer temperatures in most southern states where mercury is peaking in the mid-40s Celsius, heavy rain lashed Bengaluru on Sunday, bringing in rainfall of 35.4 mm, an official said on Monday.

"Bengaluru city has registered a rainfall of 35.4 mm on Sunday and HAL Airport has registered 10.7 mm rainfall. We are expecting light to moderate rainfall in the city and its rural areas on Monday," a Met department official told IANS.

For Tuesday, the department has forecast light to moderate rainfall in the range of 2.5 to 15.5 mm.

"In the next two days, rain is expected because there is a trough prevalent over the southern peninsula and also a system is present on the southwest Bay of Bengal," she said.

Including the city, a large number of other districts in Karnataka are also expected to receive rainfall in the next couple of days.

"There is a cyclonic circulation over the Bay of Bengal and adjoining south Tamil Nadu. This system is 5.8 km above the sea level. There is also a trough or in layman's terms wind discontinuity," said the official.

Wind discontinuity means the convergence of many winds from different directions leading to thunder showers, she said. This kind of weather is expected wherever there is a trough.

"The presence of a trough is a seasonal feature during the pre-monsoon season. It occurs primarily due to the heating of the land mass," the official said.

According to the official, as the sun moves on the northern hemisphere from March to May, the heating of land mass occurs resulting in trough formation.

She said another trough is also stretching from Chhattisgarh to interior Tamil Nadu, passing through Telangana, coastal Andhra Pradesh and Rayalaseema.

"This is the reason you can expect lots of thunderstorms if there is moisture incursion from the sea. Probability of thunderstorm taking place is quite high," the official said.

What started off as a sunny Sunday slowly transformed by afternoon with cool winds in the city to later become a heavy rain of 35.4 mm.

Meanwhile, Bengaluru denizens filed 150 complaints with the city civic body to clear trees and branches broken by the rain.

"Around 150 complaints of fallen trees and branches have been received by the BBMP control room following this evening's (Sunday) rain," tweeted Bruhat Bengaluru Mahanagara Palike (BBMP) Commissioner B.H. Anil Kumar.

Kumar said the civic body and Karnataka Fire Department are attending to all the complaints to clear the roads of the debris the rain left in its wake.

Similarly, a sunny Monday cooled off by afternoon with blowing winds and a rumbling outcast sky.

The Met department has forecast partly cloudy sky with possibility of thundershowers or spells of rain for the next six days.

"Rain or thundershowers would occur towards evening or night," the department predicted for Tuesday.

Tuesday's minimum temperature is expected to be 22 degrees Celsius and the maximum is forecast to at 34 degrees Celsius.