American and Australian climate experts have cranked down their La Niña alert, saying the phenomenon that brings greater-than-average rainfall to the Philippines may not occur in the northern hemisphere autumn after all.
Still, the US National Oceanic and Atmospheric Administration (NOAA) and Australia’s Bureau of Meteorology do not discount the possibility of occurrence later this year.
The NOAA said in its monthly update neutral conditions—when there is neither El Niño nor its opposite La Niña—were observed in the past four weeks although sea surface temperatures in the east and central part of equatorial Pacific Ocean were below average.
Cooler than usual temperatures are associated to La Niña while warmer than average readings go along with El Niño.
“The multi-model averages favor borderline Neutral-La Niña conditions during the Northern Hemisphere fall, continuing into winter,” the NOAA said.
But the agency said the forecaster consensus was partial to a stronger “neutral” status, which meant weaker chances of La Niña developing.
This “is supported by the lack of significant anomalies in several indicators over the past month,” the NOAA said, referring to winds, subsurface temperature and convection or layers of temperatures in the atmosphere.
“Overall, [neutral] conditions are slightly favored (between 55-60 percent) during the upcoming Northern Hemisphere fall and winter 2016-2017,” the NOAA said.
The Australian BoM concurred through a separate advisory, but added that “a late and weak La Niña remains possible.”
“International climate models suggest neutral to weak La Niña levels for the remainder of the year,” the BoM said. “A ‘La Niña Watch’ [alert] remains in place.”
Based on observations of the United Nations Office for the Coordination of Humanitarian Affairs (Ocha), the Philippine government through “Oplan Listo” has advised the public to prepare for the risks which the above-normal rainfall and strong monsoon activity will bring.