Lucknow, Aug. 31 -- There is a distinct possibility of heavy rainfall in the state over the next three days beginning from Sunday due to an increase in monsoon activity, the weatherman said on Saturday. Light to moderate rainfall is possible at many places and heavy rainfall between August 31 and September 2. The maximum rainfall activity will be on Monday, September 1. Some districts of the western and adjoining central part of the state have been put on orange alert for possible heavy to very heavy rainfall. Yellow warning has been issued for the state capital, Lucknow, on Monday. The city will experience moderate rainfall with possible heavy rainfall at some places, said Atul Kumar Singh, senior scientist at Lucknow Met office. Due to the possible northern deviation of the monsoon trough in the state because of the strengthening of monsoon flow and other favourable synoptic conditions which will result in increase in monsoon activities during the next 2-3 days, said Atul Kumar Singh, said. The IMD issued a yellow alert of heavy rainfall in over 24 districts for Sunday and an orange alert of heavy to very heavy rainfall likely over 18 districts of Uttar Pradesh for Monday. On Sunday, heavy rainfall is predicted at several districts of West UP including Saharanpur, Shamli, Muzaffarnagar, Baghpat, Meerut, Aligarh, Mathura, Hathras, Kasganj, Etah, Agra, Mainpuri, Firozabad, Etawah, among others. For Monday, an orange alert of heavy to very heavy rainfall likely over Lakhimpur Kheri, Sitapur, Hardoi, Farrukhabad, Meerut, Hapur, Bulandshahr, Aligarh, Kasganj, Bijnor, Amroha, Moradabad, Rampur and adjoining areas. A yellow alert, also for Monday, warns of heavy rainfall over 24 districts including Lucknow, Kanpur Dehat, Kanpur City, Unnao, Barabanki, Rae Bareli, Amethi, among others. The forecast for Lucknow is generally cloudy sky becoming overcast with a few spells of rain/thundershower. The maximum and minimum temperature will be around 32 and 27 degrees Celsius, respectively. The state forecast is rain/thundershower very likely at a few places over East UP and at many places over the West UP. Warning Heavy rain is very likely at isolated places over West UP....