KOCHI : The long-term forecast for the southwest (SW) monsoon, released by the India Meteorological Department (IMD) on Monday, indicates above-normal rainfall across the country, including in Kerala. Accounting for 70% of Kerala’s annual rainfall, the SW monsoon normally reaches state by June 1, before withdrawing by September 30.
In a major relief to the state, which has been dogged by unseasonal warm weather, the IMD forecasts widespread summer rains from April 17 to 21. Though the forecast does not provide any indication regarding the onset of monsoon, meteorologists believe SW monsoon may set in by the last week of May.
Summer rain likely to intensify
According to the forecast, the southwest monsoon is likely to be 104% of the long-period average (LPA). The LPA from 1971 to 2020 for the entire country has been 87 cm. Quantitatively, seasonal rainfall over the country is likely to be 106% of LPA with a model error of plus or minus 5%.
“The IMD has not given state-specific forecast, but it indicates that Kerala will receive above-normal rainfall. It will provide an update on the monsoon by the last week of May. El Niño, a climate pattern that causes unusual warming of the oceans, is currently moderate and is expected to become neutral by the arrival of monsoon. La Niña, a climate pattern that cools the ocean surface temperature, is likely to set in by August, So we can expect above-normal rainfall this year,” said IMD scientist V K Mini.
She said the summer rains may intensify by the end of the week, which will bring down temperatures.
A cyclonic circulation lies 0.9km off the Gulf of Mannar and it will cause scattered to fairly widespread moderate rainfall over Kerala and Mahe during April 18-21. The forecast says Kerala may receive isolated heavy rainfall on April 18 and 19.
“The summer rains are expected to intensify over the next few days. There are chances of rainfall after April 20. Globally, there has been a change in atmospheric circulation under the influence of La Niña. This may affect our weather patterns as well. The summer rains may bring some relief from the scorching heat,” said S Abhilash, director of Cusat’s Advanced Centre for Atmospheric Radar Research.