A triple ‘weather system’ brewing from Bangladesh and spanning as far as Rajasthan is anticipated to bring further relief from the blistering heat that kept scorching south Bengal for more than two weeks.

According to the Regional Meteorological Centre, two cyclonic circulations coupled with a trough line are to bring good rainfall to almost all the districts of south Bengal, including Kolkata till 14 May.

After a record spell of dry, hot and humid period of 17 days, the city was drenched with a 77mm rainfall last evening. A squall having the maximum speed of 77 kmph also uprooted several trees at several places while the mercury plummeted five degree lower. However, while the city enjoyed the much awaited respite from the heat waves, the thunderstorm and lightning killed seven people in various parts of Bengal leaving a trail of destruction.

According to the weather office, the rainfall was triggered by a cyclonic circulation lying over Bangladesh and neighbourhood jointly with another cyclonic circulation brewing over northeast Madhya Pradesh and its surrounding areas.

The dual cyclonic circulations coupled with a trough from south Jharkhand to West Madhya Pradesh now running from north Interior Odisha to southeast Rajasthan across Chhattisgarh and Madhya Pradesh is anticipated to bring further rains till 14 May to various parts of south Bengal. According to the weather scientists, the favourable synoptic conditions and strong moisture incursion from Bay of Bengal are to bring thunderstorm, lightning along with gusty wind and thunder squall activity for the next few days in larger parts of south Bengal.

As per the forecast issued by the local weather office, of the next seven days, the rainfall, thunderstorm and squally winds are expected to be higher and more intensive on 10 May, after today. For the next three days, most parts of south Bengal are tipped to have thunderstorms with gusty wind speed reaching up to 40-50 Kmph every day. The speed is expected to be higher on 10 May when a gusty wind with speed reaching 50-60 Kmph is likely to occur in Birbhum, Murshidabad, Nadia, North and South 24-Parganas districts.

The rainfall, as pointed out by the weather scientists, is to keep the mercury below normal for the next few days. Given the fact, Kolkata is tipped to have the minimum temperature around three to five degrees below normal during the next one week.