La Niña episodes occurring back-to-back are not unusual and have occurred six times in the last 10 years, according to an expert of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).
The current La Niña that developed in October 2020 is already weakening, in terms of sea surface temperature anomalies, said Ana Liza Solis, chief of the PAGASA’s climatology and prediction section.
There is also a rising probability of returning to El Niño-Southern Oscillation or ENSO-neutral, where there is neither a La Niña or El Niño, during March-April-May period, she said.
The La Niña events that we had during the last 10 year were back-to-back events so that means it is not uncommon to have a back-to-back La Niña.
The last six events were back-to-back, Solis pointed out.
Based on available data, six episodes of back-to-back La Niña have been recorded in 2007-2008 and 2008-2009, 2010-2011 and 2011-2012, and 2016-2017 and 2017-2018.
She stressed that PAGASA cannot yet say for sure that a back-to-back La Niña will develop this year “but then historically that is what usually happens after we return to ENSO-neutral condition.”
When the northern hemisphere winter period from October to December comes again, there are potential formations of La Niña, she added.
“We are not ruling out the possibility. But there are also instances that after the La Niña and ENSO-neutral condition, an El Niño also develops,” Solis said.
“Medyo napakalayo pa po at napakahaba pa so pakaabangan na lang natin yung update sa PAGASA and international prediction centers. (We are still a long way, so let’s just wait for the update of PAGASA and international prediction centers),” she said.
La Niña is usually associated with above normal rainfall conditions across most areas of the country during the last quarter of the year and early months of the following year.