Kerala,14 May:India Meteorological Department has predicted that the monsoon onset over Kerala in 2008 is likely to be on 29th May with a model error of ± 4 days.
With strengthening and deepening of monsoon winds and widespread rainfall activity, southwest monsoon advanced into southeast Bay of Bengal, Andaman and Nicobar Islands, and north Andaman Sea on 12 May, almost 8 days in advance. As on 13 May, the Northern Limit of Monsoon (NLM) passes through Lat 5.0ºN Long 86.0ºE, Lat 8.0ºN Long 87.0ºE, Lat 10.0ºN Long 89.0ºE, Lat 12.0ºN Long 91.0ºE, Maya Bandar, Lat 14.0ºN Long 95.0ºE and Lat 15.0ºN Long 98.0ºE.
Since 2005, IMD has been issuing operational forecasts for the monsoon onset over Kerala using statistical techniques. In 2007, IMD predicted 24th May as the date of monsoon onset over Kerala. Actual monsoon onset took place 4 days later. i.e., on 28th May. IMD has now prepared the forecast for the 2008 monsoon onset over Kerala based on statistical methods.
For predicting the 2008 monsoon onset over Kerala, IMD used an indigenously developed statistical model, based on the following six predictors:
i) Minimum Temperature over North-west India ii) Pre-monsoon rainfall peak over south Peninsula, iii) Outgoing Long wave Radiation (OLR) over south China Sea (iv) Lower tropospheric zonal wind over southeast Indian ocean, (v) upper tropospheric zonal wind over the east equatorial Indian Ocean and (vi) Outgoing Long wave (OLR) over south-west Pacific region.
The statistical forecast model has a model error of ± 4 days. The mean monsoon onset date over Kerala is 1 June.