The Hindu Business Line : Summer showers likely by next week in Kerala

WEATHER records of the past three years seem to suggest that summer showers will not break until early next week in the State, which is going through possibly the worst drought-like conditions to precede the season.

Summer rains are a purely localised phenomenon, a result of the interaction of a number of favourably pre-disposed parameters such as raised humidity levels and optimum ambient temperature ably supported by light winds and concomitant smooth upward drift of hot air.

Speaking to Business Line, Mr M.D. Ramachandran, Director, Met Office, Thiruvananthapuram, said that it is the upper level humidity, rather than surface humidity, that precipitates the lean season showers and is dependent on the extent of water vapour present.

There is no formal system of quantifying aggregate rainfall recorded during the summer season.

Experience of the past three years reveals that showers set in by the middle of March and last for periods ranging from 10 days to 15 days.

The fact that the March 1-May 31 period officially accommodates pre-monsoon showers makes the quantification difficult because summer showers have often merged seamlessly with pre-monsoon showers, and the latter into the monsoon proper.

According to random Met data made available to Business Line, the three-year period culminating in 2003 shows a progressive upward shift in the intensity of summer showers recorded in the State.

However, this cannot be used as a yardstick to prognosticate on the likely performance this time round.

As if that were not enough, these three years also saw the monsoon seasons failing the State by linearly rolling margins in an as-yet-unexplained pattern of events, quite in line with the legendary fickleness of the tropical weather systems.

Last year the summer showers saw a sedate but firm start on March 14, with Alappuzha recording three cm of rain.

The rainfall gained momentum but more or less prevaricated in intensity during the next four days, with Thiruvananthapuram recording six cm on March 15, Alathur five cm (16th), Thodupuzha, six cm (17th) and Parambikulam six cm (18th).

An overnight spurt saw Kannara recording 10 cm on March 19, representing the peak of the season.

The rainfall later plateaued, with Minicoy recording nine cm on March 20, Peermade five cm (21st) and Aryankavu two cm (22nd). The season petered out by March 31.

In 2002, the season set to a start on March 16-17 but returned comparatively fewer rainy episodes, before ending by March 29.

In 2001, the season saw a mediocre beginning as early as on March 6-7, but lost direction mid-way. It lasted for 15 more days, and signed off in style with Thodupuzha recording seven cm on March 30.

But aggregate rainfall for the season was the lowest recorded during the three years under reference.

Last year's good summer rains had helped hold down the temperature levels and also allowed badly needed breathing space for the drinking water supply authorities.

The run-up to the season this year presents a comparatively worse picture, with all major rivers and rivulets having dried up much earlier, jeopardising drinking water supplies in urban centres and the countryside. Three consecutive below-par monsoon years have hit the availability of potable water and cheaper hydroelectric power.

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