The rain led to waterlogging in several low-lying areas in the capital, such as Shyambazar, Hatibagan, Central Avenue, Dhakuria, and Gariahat, causing hardships to officegoers and school children. (Express Photo by Partha Paul)Heavy rainfall, accompanied by thunderstorms and lightning, is expected across West Bengal over the weekend, according to the India Meteorological Department (IMD). Favourable atmospheric conditions and strong moisture incursion from the Bay of Bengal is expected to keep the intense thunderstorm activity alive through Sunday. While the northern half of the state faces severe flood risks, the southern districts are expected to simultaneously battle high humidity and sudden, dangerous squalls.Continuous showers from the early hours of Friday brought some respite to Kolkata and adjacent districts after days of hot and humid weather, while heavy rainfall wreaked havoc in north Bengal. The rain also led to waterlogging in several low-lying areas in the capital, such as Shyambazar, Hatibagan, Central Avenue, Dhakuria, and Gariahat, causing hardships to officegoers and school children.Also Read | Why has monsoon progress stalled, and when can rains be expected next?The city had remained largely dry since the monsoon arrived on June 11. Apart from a mere 1.4mm of rainfall the day the monsoon reached Kolkata, the Met office had recorded no rain at its Alipore station in the city for six consecutive days from June 12 to 17.For Kolkata and its neighbouring districts, including Howrah, Hooghly, North and South 24 Parganas, thunderstorms accompanied by lightning and gusty winds reaching 40–50 kmph are likely. Extreme humidity is also expected to keep conditions highly uncomfortable.The highest thunderstorm activity in south Bengal is expected over Nadia, Murshidabad, Birbhum, Purba and Paschim Bardhaman, Bankura, Purulia, and Purba and Paschim Medinipur districts. These areas are likely to see frequent lightning and moderate rain, with a heat and humidity warning active for western parts like Bankura.The active monsoon core continues to present a stark contrast between regions. In south Bengal, light to moderate rain or thundershowers are very likely at many places on Friday, including Jhargram, Birbhum, Murshidabad, Nadia, Purulia, Bankura, and Hooghly, with isolated spots facing a yellow warning for lightning and sharp wind gusts up to 40-50 kmph.Concurrently, a severe high-yield monsoon surge is dominating sub-Himalayan West Bengal, prompting an orange alert for heavy to very heavy rainfall, ranging from 7 to 20 cm across Darjeeling, Kalimpong, Jalpaiguri, Alipurduar, and Coochbehar. Early morning state-level logs highlight massive localised precipitation totals, led by heavy recorded downpours at the Jaybirpara Tea Estate in Alipurduar (18 cm) and Nagarkata in Jalpaiguri (13 cm).Story continues below this adAlso Read | Delhi, Northeast brace for storm, rainfall as El Nino threatens monsoon deficitAs per the Met, north Bengal is expected to receive the heaviest and most dangerous rainfall. A maximum red alert has been issued for Jalpaiguri and Alipurduar for Saturday, with warnings of extremely heavy rainfall exceeding 20 cm that raises immediate concerns over severe flooding and waterlogging. An orange alert remains active for Darjeeling, Kalimpong, and Cooch Behar.The hill districts of Darjeeling and Kalimpong face a severe risk of fresh landslides and further road disruptions due to the torrential rain. Continuous downpours have already caused critical damage, including the total collapse of the temporary Dudhia bridge cutting off the direct Siliguri-Mirik route, and major landslides on National Highway 110, alongside the complete suspension of heritage Toy Train services.The IMD has issued a strict safety advisory urging people to avoid open fields during lightning activity, stay away from trees and electric poles, and seek immediate indoor shelter during thunderstorms.(The writer is an intern at Kolkata office of The Indian Express)