A spell of rain, accompanied by streaks of lightning and gusts of wind, on Saturday night brought temporary relief from the hot and humid conditions prevailing since late morning.
More such spells are expected in the city till Thursday, a Met official said.
“A trough of low-pressure persists over Jharkhand to south Chhattisgarh. A high-pressure zone over the Bay of Bengal is feeding moisture into the system. The high day temperatures over the past few days teamed up with the moisture to help in the formation of thunderclouds. The clouds travelled eastwards, bringing rain to the districts and Kolkata,” said G.K. Das, director, India Meteorological Department, Kolkata.
The high-pressure zone over the Bay is oscillating, Das said. “On Sunday, it descended towards south Odisha and Andhra Pradesh. But it will rise again. A couple of more spells of thunderstorms are expected in south Bengal, including Kolkata, till Thursday,” he said.
“On Monday, thunderstorms and lightning with light to moderate rainfall along with gusty winds (speed reaching 30-40kmph) is likely to occur at one or two places over East and West Midnapore, Jhargram, Bankura and Purulia districts. Thunderstorms and lightning with light rainfall are likely to occur at one or two places over the rest of the districts of south Bengal,” said a Met bulletin.
On Tuesday, hailstorms are likely at one or two places in Bankura, West Midnapore, Jhargram, Purulia, Birbhum, and East and West Burdwan districts.
Squalls (wind speed reaching 50-60kmph) with lightning and light to moderate rainfall is “very likely” at one or two places in Bankura, West Midnapore, Jhargram, Purulia, Birbhum, East and West Burdwan, Howrah and Hooghly districts, the bulletin said.
“Thunderstorms with lightning and light to moderate rainfall along with gusty wind (speed reaching 40-50kmph) are very likely to occur at one or two places over the rest districts of south Bengal,” it said.
On Wednesday and Thursday, “thunderstorms with lightning and light to moderate rainfall along with gusty wind (speed reaching 40-50kmph) are very likely to occur at one or two places over all the districts,” the bulletin said.
Between the first and second week of March, the absence of any weather system on the Bay or land had given a free passage to cold northwesterly winds. The winds dragged the Celsius down. The minimum temperature had slid below 20 degrees on a couple of days.
But since March 9, the Celsius has been on the rise. On Friday, the maximum temperature was 34.1 degrees, a notch above normal and the minimum was 26.5 degrees, four notches above normal.
“Heating is needed for the formation of rain-bearing thunderclouds,” said a Met official.
The showers and breezy conditions brought relief to Kolkatans. The effect was visible on Sunday as well.
The minimum temperature was 23 degrees, a notch below normal.