Following a damaging El Nino weather period, a US government weather forecaster on Thursday said the La Nina weather phenomenon is favoured to develop during August through October 2016.
The Climate Prediction Centre (CPC), an agency of the National Weather Service, said in its monthly forecast there is a 55-60 per cent chance that the La Nina weather phenomenon will develop during the fall and winter of 2016/17.
Last month, the CPC forecast that La Nina was favoured to develop during the Northern Hemisphere’s summer with a 75 per cent chance of it developing in the fall and winter.
La Nina, which is typically less damaging than El Nino, is characterised by unusually cold ocean temperatures in the equatorial Pacific Ocean. It tends to occur unpredictably every two to seven years. Severe occurrences have been linked to floods and droughts.
Near-to below-average surface temperatures across the eastern equatorial Pacific Ocean were observed during the past month, the CPC said.
Odds lower
US forecasters have dropped the odds a weather-roiling La Nina that can dry up crops in Brazil and trigger more Atlantic hurricanes will form by the end of 2016, but still believe it will happen.
In the past, La Nina conditions have led to droughts across southern Brazil, a major soy bean producer, and heavy rains in Malaysia that can make harvesting palm oil crops difficult. In the United States, the phenomenon has brought cooler winters boosting natural gas demand.
“We still favour a La Nina, there is still momentum in that direction,” said Michelle LHeureux, a forecaster with the Climate Prediction Centre in College Park, Maryland. “I would keep your eye on this.”
Both El Nino and La Nina must have a corresponding reaction from the atmosphere to changes in the ocean temperatures that lasts for at least a month, with the expectation that the reaction will persist even longer, before forecasters confirm the phenomenon.
Gas prices
“The odds for a La Nina have dropped because forecasters haven’t seen a reaction by the atmosphere above the ocean,” LHeureux said.
Prior to last year’s El Nino, there were times when the ocean temperature met the criteria without the atmosphere reacting to it. It is always the atmosphere, LHeureux said. The atmosphere is much less constrained.
The ocean is a big mass of water, so it cant move that quickly. Once things get going with the ocean it is almost unstoppable.
This reaction in the atmosphere also could be a key in determining gas prices going into the winter.
Colder-than-normal temperatures in large US cities during the November-March heating season would cause more of the fuel to be burned to heat homes and businesses.