VietNamNet Bridge - La Nina has returned this year but it won’t have a strong impact, according to the Central Hydrometeorological Forecasting Center.

Mr Hoang Phuc Lam

The latest report shows that the sea surface temperature in the east area of Pacific Ocean is 0.8oC lower than the average temperature of many years. Australia, Japan and the US have all confirmed the return of La Nina.

Sources said the weather would continue in the neutral phase (ENSO) in the last months of 2017, but it will lean towards a cold phase, while the possibility of La Nina returning by early 2018 is 50-60 percent.

According to Hoang Phuc Lam, head of the medium and long-term meteorological forecasting department, the center’s forecasts released in April and last month also showed that in the last month of 2017 and early 2018, the state of the ocean would change to La Nina phase with a probability of 50-60 percent. La Nina appeared in late November.

However, Lam said though the sea surface temperature has shown La Nina phenomenon, it will take some time for these changes in the ocean to affect  atmospheric circulation and manifest in different types of weather.

The latest forecasts by the Central Hydrometeorological Forecasting Center say La Nina won’t last a long time. It is expected that La Nina will decline in April or May 2018. 

The latest forecasts by the Central Hydrometeorological Forecasting Center say La Nina won’t last a long time. It is expected that La Nina will decline in April or May 2018.

La Nina mostly appears in winter and has an impact  in a complex and unclear way. The phenomenon leads to an increase in rainfall in Vietnam, the East Sea and East Asian countries.

In principle, La Nina, or the cold phase will influence the average temperature. Therefore, this winter will be colder than the previous year. 

However, Lam said the temperature this winter would be around the average temperature of recent years. It will be colder than last year, but not by much.

La Nina will also lengthen the 2017-2018 stormy season finish. Lam said typhoons or tropical low pressure would appear in December 2017 and January 2018 on the East Sea.

Some spells of serious and damaging cold may appear from now to Tet (February 2018) in the northern and central regions, mostly in January and February 2018. 

Serious cold spells with the temperature below 15oC would appear on days just before Tet, when there is northeasterly monsoon or enhanced cold air accompanied by rain.

In the central region, there will be many rains lasting 3-5 days occurring after 2-3 day intervals.