The World Meteorological Organization says El Nino conditions have become established over the tropical Pacific, a condition that will have an impact on climate around the world. WMO says this phenomenon will likely continue at least through the remainder of the year but is not expected to be as severe as previous El Ninos.
According to the weather forecasters, the world is in for a relatively easy ride this year. It says the weather anomalies expected by this year's El Nino will, in no way, cause the kind of death and destruction that occurred in 1997 and 1998.
That El Nino was one of the strongest on record, causing an estimated 23,000 deaths and about $32 billion in damages. In contrast, WMO El Nino Expert, Rupa Kumar Kolli, says this year's weather phenomenon will be rather mild.
"In terms of severity, this particular El Nino event can be classified as a weak to moderate event," he Rupa Kumar Kolli. "The temperature anomalies are about 0.5 to 1 degree Celsius above normal. And, even model predictions do not go beyond 2 degrees Celsius to the extreme.
El Nino is characterized by unusually warm ocean temperatures in the central and eastern equatorial Pacific, and La Nina is the opposite condition. It is characterized by unusually cool ocean temperatures in the eastern equatorial Pacific.
Both events can disrupt the normal patterns of tropical precipitation and atmospheric circulation. They can have widespread impacts on climate in many parts of the world.
Kolli says El Nino is typically associated with weaker monsoons in the tropics, in particular in the South Asian region.
"In fact, based on the general information that is publicly available, we are already aware that South Asia is under the grip of an intense drought because of the weak, very weak monsoon activity," said Kolli.
Kolli says most of the impacts are seen in the tropics because the event is of tropical origin. But, he notes there are impacts also in regions of higher latitude.
"It does affect Africa," he said. "Africa, particularly eastern Africa is known to have drier than normal conditions due to El Nino from a climatological point of view … For North America, the climatological expectation is that the current hurricane season will be weaker than normal. So, that is one notable aspect."
Meteorologists say temperature changes that occur during El Nino and La Nina events are strongly linked to major climate fluctuations around the globe, and, once they have begun, such events can last for 12 months or more. They say the pattern of such events are never exactly the same.