We are expecting the prevailing wind conditions to strengthen over the next 2-3 days before monsoon rains occur in Kerala, DS Pai, head of long-range monsoon forecast, IMD, told FE from Pune. He said pre-monsoon showers have already occurred in Kerala and many parts of the country, and the monsoon is set to hit Kerala over the next 3-4 days.
Conditions are also favourable for the further advance of the southwest monsoon into some parts of south Arabian Sea and parts of Bay of Bengal during the next 48 hours, IMD said in a released statement.
After the actual onset of monsoon rains in Kerala, we will give advance sequence of its progress across the country, Pai said. After arriving in the Kerala coast, the monsoon rains cover major parts of the country during June-August.
Since 2005, IMD has been issuing operational forecasts for the date of the onset of monsoon in Kerala using an indigenous statistical model with a model error of four days.
Last month, science and technology minister S Jaipal Reddy had released the first long-range forecast for the southwest monsoon by IMD. According to the Met department, quantitative seasonal rainfall during the monsoon months (June-September) is likely to be 98% of the long-period average (LPA), or the average countrywide annual rainfall (89 cm) recorded between 1951 and 2000.
Using a combination of dynamic and statistical models, the IMDs forecast stated that rainfall during the monsoon months would most likely be normal, in the range of 96-104% of the LPA. Reddy said that the probability of a normal monsoon was high.
In April last year, IMD had predicted normal rainfall of 99% of the LPA for the four monsoon months while actual rainfall turned out to be only 92% of the LPA, leading to many parts of the country, including Maharashtra, Gujarat and Karnataka, facing drought-like conditions.