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El Nino Advice
A strong El Niño in the Pacific Ocean continues to dominate the countries that border the Pacific oceans. All indicators and previous records shows further warming remains possible and all international climate models indicate that the strong El Niño is likely to persist until the end of 2015 before and decline during the first quarter of 2016.

What is El Niño?
El Niño is the movement of warm ocean water from the north of Australia to South American crossing the Pacific Islands every 3 to 7 years. The movement of this warm water changes the weather patterns in many countries including Tonga. El Nino usually lasts for 1 year.

Effects of El Niño on Tonga’s Climate and Activities
For Tonga, El Niño usually brings cooler night time temperatures from May to October, hotter day time temperatures from November to April, less rainfall and more cyclones than usual. El Niño years are excellent for growing sweet potatoes (provided enough water is given) and crops that depend on cooler night time temperatures but no good for rain dependant crops in the Summer time. Fruit trees and Vanilla also tend to do well during El Niño due to stress induced flowering. Tuna fisheries tend to be poor during this time due to tuna stocks migrating away from Tonga waters.

Current Situation

Rainfall received across the country during October was drier than normal across the country, refer to Table 1. Lowest rainfall was recorded in Nuku’alofa was 10.1mm which is the second lowest rainfall in its record for October and Fua’amotu recorded 19.6mm which is the lowest in its record of 36 years for October.

TABLE 1: Monthly rainfall from August to October 2015

Drought Analyser and rainfall outlook

Rainfall in the last 3 months (August – October) was drier than normal in the Niuas and normal elsewhere. The amount of rainfall that fell in August and September eased the drought conditions during these two past few months in Vava’u, Ha’apai and Tongatapu but lack of rain in October has brought back drought warnings for those locations.

Rainfall forecast for the next 3 to 6 is for drier than normal conditions across Tonga.  Warmer than average daytime temperature are likely across the country in the next 3 months. This pattern of three month outlook is typical of El Niño years.  

Recommended actions for the next 3-6 months

Tonga is now in the middle of a strong El Niño and the rainfall outlook for the coming 3 to 6 months is likely to be drier and temperatures warmer than normal with higher chance of tropical cyclone occurrence.  It is advisable especially for the smaller islands that do not have ground water to collect as much water as possible when it rains and use it wisely for drinking purposes only.  Planners are encouraged to activate their drought response and tropical cyclone plans and remain on the alert for the possible continuation of below average rainfall and hotter conditions for the next 6 months. Rainfall and tropical cyclone sensitive sectors such as Agriculture and Fisheries (Food Security), Health, Water Resource Management and Tourism should take extra measures in public awareness and continue drought operations and tropical cyclone planning and the conservation of rain water. The public are encouraged to continue to seek advice from the relevant authorities e.g. Ministry of Agriculture and the National Emergency Management Office (NEMO) on the best practices to minimise the effects of El Niño.
    
Here are some simple actions and practices that can be done to mitigate the effects of El Nino.

The next El Niño Advisory will be issued in early December 2015.

Meteorology Division of the Ministry of Meteorology, Energy, Information, Disaster Management, Environment, Climate Change and Communications