Written by Aryesh Chakraborty September has emerged as a game-changer for Pune’s monsoon season, with the city recording 316.7 mm of rainfall during the month, an excess of 116 per cent above the normal 146.3 mm, according to the India Meteorological Department (IMD). The late surge not only offset the rainfall deficits of July and August but also pushed Pune’s overall seasonal tally from June-September to 849.2 mm, about 33 per cent above normal. Data from the Pune Weather Observatory further indicates that Shivajinagar alone received 849.3 mm of rain between June 1 and September 30, highlighting the intensity of this year’s monsoon. The impact of the rains in late September was felt across Maharashtra, as heavy showers lashed Pune and other regions, including Marathwada. The IMD had issued warnings for excessive rainfall during this period. The downpours caused widespread damage to crops and property, particularly in rural areas, further compounding the challenges already faced by farmers who had been affected by erratic monsoon patterns earlier in the season. According to S D Sanap, senior meteorologist at IMD Pune, Pune’s unusually high rainfall in September was primarily caused by two back-to-back low-pressure systems (LPS) forming over the Bay of Bengal. “These systems moved westward and northwestward across Vidarbha, Marathwada, and Madhya Maharashtra, bringing heavy showers to Pune and surrounding regions,” he explained. A low-pressure system(LPS) is a weather area with lower atmospheric pressure than its surroundings, creating winds that converge at the centre and rise upward. This upward motion of air leads to cloud formation and precipitation, causing unstable and often stormy weather, including rain and strong winds. Sanap added that while July and August received below-moderate and normal rainfall, the movement of these LPS in September resulted in a significant surge. “The late-season showers were directly linked to the dynamics of these systems as they traversed across the state, causing concentrated rainfall over specific areas,” he told the Indian Express. Looking ahead, the Pune Weather Observatory has forecast a decrease in rain intensity after September 30, with only scattered showers expected in some districts. Adding to that, Sanap explained that the residing factor of LPS will see Pune receiving light to moderate rainfall from October 2-3. Aryesh Chakraborty is an intern with The Indian Express.