Widespread Rainfall Alert
The Indian Meteorological Department (IMD) has activated a substantial weather alert for West Bengal, projecting a period of intense rainfall from May
1st through May 7th. This advisory covers both the northern and southern districts, predicting a pattern of widespread to extensive rain and thunderstorms. The primary drivers behind this persistent wet spell are identified as an active low-pressure system brewing in the Bay of Bengal, coupled with strong southeasterly winds that are channeling considerable moisture inland. This atmospheric confluence is expected to sustain the precipitation across the state for the first week of May, with activity gradually diminishing but persisting into the second week. This broad alert underscores the widespread impact of the current weather phenomena, necessitating preparedness across numerous regions of West Bengal.
Key Weather Drivers
The current unsettled weather gripping West Bengal is largely orchestrated by a confluence of atmospheric conditions. A crucial element is the low-pressure system situated over the Bay of Bengal, which acts as a focal point for moisture convergence. This is further amplified by a steady stream of humid air originating from the southeast, feeding directly into the state. Meteorologists also point to an upper air cyclonic circulation, observed at approximately 0.9 km above sea level, influencing the skies over Gangetic West Bengal and neighboring Bangladesh. Complementing these are a trough extending from Uttar Pradesh through Odisha and Chhattisgarh. The interplay between these systems and the warm surface temperatures, combined with the abundant moisture, intensifies convection, leading to the characteristic pre-monsoon thunderstorms, often referred to as 'Kalbaishakhi'. However, the current scenario is notable for its widespread nature and persistence, attributed to multi-layered atmospheric support.
South Bengal Impact
South Bengal is experiencing a significant brunt of the recent weather patterns, with several districts recording substantial rainfall. Kolkata, for instance, has seen record rainfall for April, with observatories documenting considerable amounts within short periods. On one occasion, Canning recorded 108 mm of rain in 24 hours, and Alipore in Kolkata noted 54.2 mm during a specific downpour. This led to a noticeable drop in temperatures, with maximums falling by 8 to 10 degrees Celsius. Districts such as Howrah, Hooghly, North and South 24 Parganas, and Nadia have been hit by light to moderate rains accompanied by thunderstorms. Specific advisories highlight isolated heavy rainfall and gusty winds up to 50-60 kmph in Nadia and the 24 Parganas. Coastal areas like East and West Midnapore, and Jhargram, are witnessing frequent thunderstorms with winds of 40-50 kmph, posing risks of localized disruptions. Even western districts like Bankura, Purulia, and Bardhaman have experienced extreme weather, including isolated hailstorms and squalls reaching up to 62 kmph.
North Bengal Intensifies
While South Bengal has seen considerable precipitation, North Bengal is emerging as the zone experiencing the heaviest rainfall. Districts including Jalpaiguri, Alipurduar, and Cooch Behar are anticipated to receive particularly intense downpours, with the IMD forecasting heavy to very heavy rainfall, potentially ranging from 7 to 20 cm, over the coming days. Recent observations confirm this, with some tea garden areas in Jalpaiguri and Alipurduar reporting between 4 to 7 cm of rain, and Maynaguri in Jalpaiguri recording 7 cm. This extensive rainfall in the northern districts raises concerns about potential waterlogging, escalating river levels, and the possibility of flooding. Furthermore, the hilly districts of Darjeeling and Kalimpong are expected to face widespread rainfall, prompting authorities to flag the heightened risk of landslides and periods of reduced visibility due to dense fog and clouds.
Fishermen Advisory
A specific and critical advisory has been issued for the fishing community operating along and off the West Bengal coast. Between May 1st and May 4th, fishermen are warned of squally winds with speeds ranging from 40 to 50 kmph, potentially gusting up to 60 kmph. This forecast necessitates caution and is expected to impact maritime activities in the region. The broader meteorological outlook for both North and South Bengal indicates continued fairly widespread to extensive rain and thunderstorm activity throughout the first week of May. While the intensity is projected to gradually decrease, the weather system is anticipated to persist into the second week of May, maintaining a spell of unsettled conditions across the state. Residents are urged to stay informed and take necessary precautions, especially during periods of lightning and heavy downpours.
