Despite some initial bouts of pre-monsoon showers, many places in Kerala have been witnessing unusually high temperature. However, weather experts are of the view that the southwest monsoon is likely to start on a grand note in Kerala this time after a below-normal pre-monsoon rainfall.
As on May 21, the pre-monsoon rain was 26% deficient in Kerala, leading to a rise in temperature and humidity — a combination of which causes people discomfort during day time. A senior India Meteorological Department (IMD) scientist told The Hindu that the unusual rise in temperature over the land mass is likely to strengthen the monsoon trough. Further, it will lead to the development of low pressure belts over land mass, which is likely to draw more moisture-laden winds from the Indian Ocean to the land.
As a result, the State is likely to receive good rainfall in the first two months of monsoon. For instance, in the last two previous monsoon seasons, May recorded excess rainfall, but rain was deficient in June and July. Last year, May registered 94.5% excess rainfall, but June witnessed 52% drop in rainfall. So, the shortfall in the current pre-monsoon season (March, April and May) and above-normal maximum day temperature, indicates that it would be a grand start for monsoon this year, he said.
Temperature difference
“It is true that temperature difference in the land and sea plays a major role in the strengthening of monsoon. However, the temperature variation in Eurasia has a major bearing on the monsoon rather than the temperature fluctuation in a small State like Kerala. But the overall development indicates that the onset of monsoon in Kerala is likely to be on a positive note this time. Further, the chances for the development of a positive phase of IOD (Indian Ocean Dipole) in the western parts of the Indian Ocean which normally leads to greater monsoon rainfall and more active (above normal rainfall) monsoon days, promises a good season for Kerala and coastal Karnataka,” said D. Sivananda Pai, former Director, Institute for Climate Change Studies, Kottayam. Normally, June and July account for the lion’s share of southwest monsoon rainfall in Kerala.
