With rainfall severely down for December, the Met office is warning that water will have to be tightly conserved and a watch kept for a possible recurrence of the El Nino conditions which brought drought here in 1997/98.

December this year was the driest for the corresponding period in the last six years, according to statistics provided by the Hydrometeorology Service of the Ministry of Agriculture.

It is also expected that the dry spell will extend into the first quarter of the new year and current climate models indicate that another spell of the El Nino phenomenon may follow the current aridity. At present, predictions into the long term cannot be made with a very high degree of accuracy, the Met office said.

A release from the Chief Hydrometereological Officer, Dilip Jaigopaul said that the average rainfall in December is 261.9 mm but "since August, with the exception of September, the period had received below normal rainfall". As off December 28, rainfall recorded for the month was 63.6 mm compared to 200.8 mm last year.

Jaigopaul is also encouraging farmers, fishermen and others whose professions depend on weather patterns to make use of the `Hydrometereological Corner' a weekly feature provided by the Hydromet Service and sponsored by the World Bank in collaboration with the International Development Association in the Sunday Stabroek, the Sunday Chronicle and the Mirror newspapers.

Jaigopaul said that climatologically, from mid-November to January, the secondary wet season, rainfall results primarily from the Inter-tropical Convergence Zone (ITCZ). There was evidence, however, of this season being missed in previous years.

Although the ITCZ has been discerned, he said in the release that its intensity this year has not been sufficiently significant to produce the quantity and intensity of rainfall. Rainfall interpretation from satellite pictures received over December indicate quite a spread of rainfall in all regions but the amounts were quite small.

Even though slightly warmer than normal ocean waters were being observed in the equatorial Pacific, Jaigopaul said that current conditions in the tropical Pacific are closer to neutral than either El Nino or La Nina (higher than average rainfall). Over the last few months, there have been warmer than average temperatures in the tropical central Pacific but the Met office pointed out that slightly warmer sea surface temperatures alone do not bring about an El Nino.

Current climate models have indicated that other parameters are pointing towards a gradual transition to an El Nino phenomenon but due to "the small amplitude in the anomalies, predictions into the long term cannot be made@ accurately.

According to the World Health Organisation (WHO), research is now centred on the ability to predict El Nino events several months in advance. These forecasts are only experimental at the moment but their accuracy and reliability is expected to improve in the near future. Because El Nino events evolve over several months, it is already possible to give advanced warning of many impacts once the onset of an event has been confirmed.

El Nino, according to the WHO, results from unusually warm current flows off the western coast of South America. Its appearance after Christmas led sailors in Peru to christen it El Nino, the Christ Child in Spanish.

During the March 1997/March 1998 El Nino in Guyana, there was a grave water shortage in all the country's administrative regions, brush fires and a surge in water borne diseases. Sea water had also begun to flow upstream in many of the country's rivers. Agricultural production that year dropped.

According to the WHO report on El Nino and its health impact, the El Nino events 1982 83 and 1997 98, the most recent, were the biggest this century.

* El Nino events occur irregularly, about every 2 7 years.

* They last from 12 to 18 months.

* The El Nino event begins with the weakening of the prevailing winds in the Pacific and a shift in rainfall patterns.

* The events are associated with extreme weather (floods and drought) in countries surrounding the Pacific and much further afield.

* Prolonged dry periods may occur in South East Asia, Southern Africa and Northern Australia and heavy rainfall, sometimes with flooding, in Peru and Ecuador.

* During a typical El Nino, the Asian monsoon season usually weakens and is pushed towards the equator, often bringing summer drought to north west and central regions of India and heavy rainfall in the north east.