Spike In Pre-Monsoon Weather Over Bihar, Jharkhand, West Bengal: Heavy Showers Likely

Key Takeaways:

• Kolkata recorded 54 mm rainfall, nearly meeting monthly normal in one day
• Chaibasa received 71 mm, indicating strong localized activity
• Pre-monsoon showers to continue for next week across eastern states
• No extreme heat expected in early May, temperatures likely to stay controlled

Pre-monsoon activity is on the rise over the eastern states of the country. Parts of West Bengal, Jharkhand and the foothills of Bihar witnessed moderate to heavy showers in the past 24 hours. The poll-bound city of Kolkata received heavy showers yesterday. Both the observatories at Alipore and Dum Dum recorded 54 mm rainfall in 24 hours. This was the heaviest downpour and nearly meets the normal monthly rainfall figure at both locations. Chaibasa in Jharkhand received 71 mm rainfall during this period. More showers are likely over the next one week.

Multiple factors are pooling together to enhance the pre-monsoon activity over the eastern states. There is a cyclonic circulation over Southeast Uttar Pradesh and adjoining Bihar. Another cyclonic circulation is placed over Northeast Bangladesh. The trough joining these two systems is passing across the border areas of Bihar and Jharkhand and Gangetic West Bengal, and further on to the northeastern region through Bangladesh.

Scattered heavy rain and thundershowers are expected along the foothills of Bihar, interiors of Jharkhand and the southern half of Gangetic West Bengal, including the capital cities of Patna, Ranchi and Kolkata. Lightning strikes accompanied by gusty winds are likely. Strict caution needs to be exercised to avoid exposure to lightning strikes. The weather activity will continue, maybe on a lesser note, during next week as well. With the persistent weather activity, the day temperatures are likely to get contained. Extreme heat is not expected during the first week of May 2026. A broad clearance is more probable at the start of the second half of May.