Mumbai was lashed by moderate to heavy rainfall, accompanied by thunder, on Monday morning, bringing respite from the simmering, humid weather. This downpour in the city comes as monsoon showers in Maharashtra are set to start late.Dark clouds gather over Mumbai on Sunday. The India Meteorological Department (IMD) has forecast an increase in rainfall activity from Monday and said the southwest monsoon is likely to reach Mumbai by June 23. (HT Photos )The India Meteorological Department (IMD) has forecast increased rainfall activity from Monday and said the southwest monsoon is likely to reach Mumbai by June 23.Some areas of Mumbai recorded intense showers in just one hour, civic officials said, PTI reported. The city began seeing rainfall on Sunday, with overcast skies and a cool breeze making the morning pleasant across the metropolis.Also read: 54 injured, 18 missing after major explosion at Qatar's Ras Laffan natural gas hubThe Monday morning showers reduced visibility, affecting traffic at some locations, officials were quoted as saying.IMD forecastThe IMD has issued a yellow alert for Mumbai, Thane and Raigad for the next three days, forecasting moderate rain accompanied by thunderstorms, lightning and gusty winds of 40-50 kmph.Also read: Viral video shows NEET retest paper leak, NTA fact-checks claim: ‘FAKE’While the southwest monsoon generally reaches Mumbai around June 10, this year its onset has been delayed. The monsoon advanced into South Konkan earlier this month, but its further progress was stalled due to unfavourable weather conditions.BMC issues orange alertCiting IMD's weather alert, the Brihanmumbai Municipal Corporation (BMC), on Monday, issued an orange warning for Mumbai, forecasting thunderstorms accompanied by lightning and moderate to intense spells of rainfall. Along with this, the BMC has also forecast gusty winds reaching speeds of 30-40 kmph at isolated places over the next three hours.Also read: Shashi Tharoor's Kashmir visit sparks row, snowballs into Congress vs Congress tiffResidents have been advised to take necessary precautions during thunderstorms and heavy rain spells, while several parts of Mumbai, including Bandra East, witnessed pre-monsoon showers accompanied by lightning and thunderstorms on Monday morning. The rainfall caused waterlogging and traffic disruptions in some areas.The island city recorded an average rainfall of 17 mm between 6 am and 7 am; the western suburbs received 10 mm, and the eastern suburbs recorded no measurable precipitation during the period, as per data released by the Brihanmumbai Municipal Corporation (BMC).Savitribai Phule BMC School at Worli Naka in the island city recorded 61 mm of rain in an hour, followed by G-South ward (Prabhadevi) at 58 mm, Adarsh Nagar School in Worli and Malabar Hill at 44 mm each, Worli Fire Station at 42 mm and F-South ward (Parel) at 41 mm.In the western suburbs, Pali Chimbai School and Supari Tank BMC School, both in Bandra, recorded 70 mm of rainfall each. H-West ward office (Khar) received 30 mm of rain, followed by Bandra Fire Station at 28 mm and Banana Leaf and Juhu Dispensary at 25 mm, the civic body said.