CHENNAI: Heavy rainfall lashed parts of western TN on Monday, with Hosur recording the highest of 12 cm in 24 hours. The India Meteorological Department (IMD) has forecast continued heavy rain in many western and adjoining districts, while the city and its suburbs are likely to receive light to moderate rain on Tuesday. According to IMD deputy director general (addl charge) B Amudha, “On Tuesday, the city and the suburbs may receive light to moderate rainfall over some areas, accompanied by thunderstorms and lightning. Skies will be partly cloudy, and maximum and minimum temperatures may hover around 33-34°C and 26-27°C.” She added that day temperatures are likely to stay below normal till Tuesday and may gradually rise by 2-3°C thereafter. The IMD has forecast heavy rainfall (6 cm-12 cm) for Coimbatore, Tirupur, Theni, Dindigul, Erode, Krishnagiri, Dharmapuri, Salem, Tirupattur, Vellore, Ranipet, and Tiruvannamalai districts on Tuesday. The Nilgiris district may receive very heavy rainfall, between 6 cm and 20 cm, in 24 hours. The widespread rain is due to an upper air cyclonic circulation over the west-central and adjoining southwest Bay of Bengal, extending between 1.5 and 5.8 km above mean sea level, and tilting southwestward with height. Around May 22, a low-pressure area is likely to form over the east-central Arabian Sea off the Karnataka coast and may intensify as it moves northward.An IMD bulletin noted that TN, Puducherry, and Karaikal received 192.7 mm of rainfall since March 1, which is 90% above normal. The southwest monsoon is expected to begin over Kerala around May 27, and rain activity may spread to TN shortly after. On Monday, Nungambakkam and Meenambakkam observatories recorded 1.2 mm and 4.4 mm of rainfall. Day temperatures dipped to 33.9°C and 34.5°C, which were 3.5°C and 3.9°C below normal, respectively. Blogger Pradeep John, in an online post, said, “There is some more rain expected till Wednesday for north TN, including Kancheepuram, Tiruvallur, Chengalpet, and Chennai.”