As the southwest monsoon has crossed half of its four-month course, Kerala is staring at a deficient season, contrary to the earlier forecast of above normal rainfall issued for the southern peninsula by the India Meteorological Department (IMD).
Normally, June and July account for the lion’s share of southwest monsoon rainfall in the State with these two months alone contributing to an average rainfall of 648.3 mm and 653.5 mm, respectively, out of the total long period average of 2,018.7 mm rainfall during the season.
But as of July 30, the southwest monsoon rainfall is 34% less than the seasonal average in the State. Further, the skewed spatial distribution has widened the rainfall deficit in nine districts, with Idukki accounting for the highest rain deficit of 51% followed by Wayanad and Kozhikode with 47%.
The shortfall in rain has also pushed the Kerala State Electricity Board (KSEB) to take urgent measures to conserve water in the remaining period. As of Sunday, only 36% of water is remaining in the reservoirs controlled by the KSEB. Worryingly, the latest long range forecast issued by the IMD indicates that rain activity is likely to be subdued till August 10, except for a few moderate isolated spells at the beginning of the month.
Extreme rainfall unlikely
The experts in the Institute of Climate Change Studies (ICCS), Kottayam, which takes stock of the performance of the monsoon, pointed out that August was unlikely to witness any extreme rainfall events like in the past few years as per the current metrological features.
The weak El Nino conditions in the central-eastern equatorial Pacific, which is associated with reduced rainfall activity in the Indian subcontinent due to the warmer sea surface temperature in the equatorial Pacific Ocean, have strengthened gradually to moderate El Nino now. This is likely to have an adverse impact on the monsoon rainfall in August and September. The Indian Ocean Dipole (IOD), characterised by above normal sea surface temperature in the Indian Ocean which is expected to minimise the impact of El Nino, is yet to reach a positive value.
“All models, however, suggest a positive IOD is likely to develop in late August or early September. Though we still expect normal rainfall in August and September, it is unlikely to narrow the rain deficit in Kerala, as per the current synoptic conditions. However, the weathermen are not ready to rule out an intense spell during the fag end of August or early September as it is difficult to forecast the broader contours of evolving monsoon in a tropical climate,” said an IMD scientist.
