If there is extremely heavy rainfall this weekend as forecast by the India Meteorological Department (IMD), it might set a record for the highest 24-hour June rainfall in recent years.  More than 200 mm rain has been predicted by the IMD.  On june 2 mumbaikars got some respite from the sweltering heat. Usually, the first showers hit Mumbai on June 7-10 but this time, the rains arrived in Kerala three days early as well.  While there were short bursts of heavy rain on  Monday, Tuesday and Wednesday saw no rainfall. Showers since Saturday have been categorised as pre-monsoon but IMD is positive of the monsoon reaching Mumbai by June 9.  It may be good news for Mumbaikars but the intensity of the showers will be in extremely heavy category.  Private weather forecasting agency Skymet has forecast the onset of the monsoon on Thursday in Konkan, Goa and central Maharashtra. It has forecast spells of rain in Mumbai soon. In 1991 the highest rainfall was for 399 mm.  “We have forecast extremely heavy rainfall so that people can take precautions. It is a little unusual for the monsoon to come with heavy showers, but this has happened in the past. People should not compare this to the 2005 floods and panic. It may even rain less than expected,” said Ajay Kumar, senior scientist with IMD. On June 7, 2008 (161.7mm) and June 10, 2013 (181.1mm), heavy rains coincided with the arrival of the monsoon.