Here is some cheering news on the monsoon front. The countdown has finally begun for its onset over Kerala. According to the India Meteorological Department, conditions are fast becoming ripe for the system to set in during the next 3-4 days. The normal date of the onset is June 1. Experts at the IMD said numerical weather prediction models indicated that the west-south-westerly cross-equatorial wind flows from the southern hemisphere, which bring in the monsoon, were steadily becoming faster and deeper. Wind speed The models indicated that during the next 3-4 days, the speed of the wind could go up to the range of 15 to 20 knots (about 30 to 40 kmph) and its depth to about 6 km from the surface upwards, the threshold limits. In addition, an east-west shear zone was forming over the south peninsula along the nearly 10 degree north latitude. These factors, along with an offshore trough already in place extending from Karnataka to Kerala coast, with an embedded low pressure area over the southeast and adjoining east-central Arabian Sea, mean that the monsoon is almost on the doorsteps of Kerala. The developments are almost on the lines of the forecast made by the IMD on May 14 that the monsoon could set in over Kerala on May 29, with a model error of plus or minus four days. Annual forecast The IMD, in its annual, long-term forecast issued on April 16, predicted that the rainfall for the entire season and for the country as a whole is likely to be 99 per cent of the long period average, with a model error of plus or minus five per cent. The department has been issuing operational forecasts for the onset of monsoon since 2005. Last year, it forecast that the monsoon was likely to set in on May 24 and the actual onset was four days later on May 28. In 2006, the forecast was for May 30, and it set in four days earlier