El Nino brings cooler night temperatures

Tonga is currently experiencing strong El Nino conditions bringing cooler night time temperatures, with the lowest recorded at 14.6°C for November, in Fua'amotu. However, the lowest temperature so far for the year was 12.0°C in August.

Tonga's Meteorological Division on 11 December said El Nino brings cooler nighttime temperatures, less rainfall and more cyclones than usual is near its peak.

Tonga's coolest temperatures normally occur around June-July. Having a lowest temperature of 14.6C in November may seem strange to some as this is occuring during our warm/wet season (summer), but from a meteorological point of view this lowest temperature for November is reasonable and explainable, taking into consideration several factors that affect our temperatures here in Tonga, said a spokesperson from Tonga Met.

The maximum daytime daytime temperature in November was 32.7° C in Niuafo’ou.

Rainfall

Meanwhile, rainfall received throughout Tonga last month was wetter than normal over Niuatoputapu and Niuafo’ou, normal in Tongatapu and Vava’u but below normal in Ha’apai.

The wet conditions over the two Niuas were due mainly to the rain associated with Tropical Cyclone Tuni which passed over the north of the Niuas on November 27-29.

This was the first tropical cyclone in the Southwest Pacific for the 2015-16 season and without it the impacts of lesser rainfall over the Niuas by now would have been more severe.

For the last three months, rainfall was normal in Vava’u and Niuatoputapu and below normal throughout the rest of Tonga.

Rainfall forecast for the next three to six months is for below normal conditions for Tonga, and Tonga Met advised the public to collect as much water as possible.

"Tonga is now in the middle of a strong El Nino and the rainfall outlook for the coming six months is likely to be drier than normal with higher chance of 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," Tonga Met stated.

Planers are advised to activate their drought response and tropical cyclone plans and to remain on alert for the possible continuation of below average rainfall for the next six months.

Peak

"The strong El Nino is likely approaching its peak with model outlooks suggesting that it is likely to begin declining early next year, although impacts from the event may persist much further into 2016.

El Nino is the movement of warm ocean water from the north of Australia to South America crossing the Pacific Islands every three to seven years. The movement of the warm water changes the weather patterns in many countries. El Nino lasts for one year.