Rain deficit likely to widen in Keralam, putting further strain on reservoir levels

A view of Palakkad’s Malampuzha reservoir.

Keralam is likely to experience a relatively long dry spell through most of November following nearly two weeks of scattered rainfall triggered by successive cyclones in the Bay of Bengal. An approaching easterly wave is expected to bring some showers to isolated pockets towards the end of this week. However, rainfall activity is likely to remain subdued thereafter, with the Bay of Bengal expected to remain largely devoid of significant weather systems after Cyclone Murasu makes landfall along the coast of Andhra Pradesh by Monday night or in the early hours of Tuesday.

The India Meteorological department (IMD), in its monthly forecast, has warned of below-normal rainfall in Keralam during November. The extended-range forecast issued by the IMD also indicates bleak rainfall prospects in the State over the next two weeks, except for light showers triggered by an easterly wave in isolated areas towards the end of this week. The anticipated dry spell is likely to put further pressure on the State’s reservoirs, which are banking on substantial rainfall during the northeast monsoon season to replenish their storage levels following a deficient southwest monsoon.

Speaking to The Hindu, Neetha K. Gopal, Director of IMD, Keralam, said the State had experienced a brief spell of cooler nights towards the end of October, as atmospheric conditions became stable, resulting in a drop in night-time temperatures and misty mornings. Rainfall activity is likely to take a pause after this week, with easterly winds expected to weaken. Although an average of four to five cyclones form during the northeast monsoon season, it remains to be seen whether any major weather systems will develop over the Bay of Bengal in November, as the Madden-Julian Oscillation (MJO) is moving into an unfavourable (suppressed) phase for the region, she said.

The State has so far received 275.3 mm of rainfall as of November 2, against the normal of 323.6 mm for the period, representing a deficit of 15%. Keralam normally receives 491.9 mm of rainfall during the northeast monsoon season from October to December, with the major share of the seasonal rainfall occurring in October. The water level in the Idukki reservoir, which serves the State’s largest hydel power project, currently stands at just 62.74% of its total storage capacity while the Banasura Sagar reservoir in Wayanad has 78.33% of its storage capacity filled.

With the southwest monsoon already ending with a deficit of 28%, any further shortfall in rainfall during the remaining northeast monsoon season could ring alarm bells for the State’s agricultural and power sectors.