The topic of whether there will be an El Nino pattern this summer has meteorologists coming down on both sides of the fence. "One of the strongest Kelvin Waves of the last two years is moving towards the Eastern pacific and may be the precursor to the return of El Nino," said Scott Yuknis, meteorologist with Climate Impact Co., a suburban Boston weather consulting firm. A Kelvin wave is a vast accumulation of subsurface warming in the equatorial Pacific Ocean that has reached the northwest coast of South America.
"What that usually signifies is the potential for El Nino to return," he said. "The subsurface warming has been very impressive and this has been the most significant ocean warming event of the last two years. It hasn't produced any warmth, however, on the ocean surface which is what is monitored to determine if an El Nino is in place. Most of the time when the temperature environment is going to change from El Nino to La Nina the subsurface tells you what is coming."
Yuknis added that there are a lot of complex questions in play, but the surface in the Eastern Pacific has not yet warmed. The warming of the Eastern Pacific and the development of an El Nino is extremely important in determining the U.S. summer weather outlook and the severity of the hurricane season.
"What is needed is another warm water surge to make its way across the Pacific and enhance the warming currently underway to bring the warmth to the surface. Such a movement is under way, he said. If that warmth makes it to the surface, there will be an El Nino this summer."
The models from the Bureau of Meteorology in Australia and the NWS both forecast that to happen. "It's my view that this is very uncertain and there will be a neutral ENSO this summer," said Yuknis. "There is a lot of disagreement as to what is going to happen. I think you can say that the Kelvin waves are causing the temperature volatility. Activity in the tropics is having a big impact on U.S. weather. These oscillations in water temperature are what are causing the volatility in the U.S. thermal pattern, and may or may not add up to changes in the big picture. This attempt at warming in the Eastern Pacific will be producing temperature volatility that will be taking place over the next two weeks."
The Australian Bureau of Meteorology said that the majority of models predict neutral conditions during this period with temperatures somewhat warmer than average, while about one-third of them predict an El Nino. The POAMA model, run at the Bureau of Meteorology, is strongly in favor of an El Niņo event developing during the southern hemisphere autumn and winter. The lack of consensus among the computer models is evidence for why the March to June period is known as the "predictability" barrier, where model skill is at its lowest predicting accuracy.
While some believe the chances are strong for a significant El Nino, others don't currently see it in the cards.
"I think there is a weak El Nino going on, but I believe we are getting a little carried away with El Ninos and La Ninas nowadays," said Accuweather Senior Meteorologist Joe Bastardi. "For instance, it's like someone saying that there is the possibility of snow." Bastardi said in the snow analogy, what is important is whether there is going to be a foot of snow or an inch of snow.
The meteorologist said currently if this El Nino was a snow storm, it would only be a couple inches of snow. "It's not that big a deal," he told NGI. "I don't think right now looking at it that the El Nino will affect the hurricane landfall intensity forecast that we have out to our clients."
Bastardi's current hurricane forecast for the Atlantic currently calls for five landfalling storms, one major hurricane and at least six shutdown days in the Gulf of Mexico. "I think it is another above normal landfalling season for the U.S. coastline, but less than last year," he said. The meteorologist added that it is also likely that damage and natural gas industry impact will be above normal.
"If there was an overpowering El Nino, I would remind you that we had both Hurricane Andrew and Hurricane Alicia in El Nino years," Bastardi noted. "One could argue that the greater the threat of an El Nino, the greater the threat of a Gulf of Mexico storm that would adversely impact the natural gas industry."
Bastardi said he believes the weather forecasting community needs to be a little bit more cautious with their speculations about El Nino and La Nina. "What you're seeing now is everybody spazzing out over the pulsing that is going on in the Southern Oscillation Index. In other words, there are these big pulses up and down that are occurring and because of that...people are saying 'here it comes.'
"All I keep seeing is that these pulses keep going back and forth and I keep seeing cold water off of South America trying to counter it," Bastardi said. "Looking at the current overall weather pattern, it wouldn't surprise me if there was a weak El Nino, but as of this time, it does not affect the criteria I look at for landfalling storms. I don't forsee the El Nino pattern becoming overpowering." (Copyright 2004 Intelligence Press Inc. All rights reserved. The preceding news report may not be republished or redistributed, in whole or in part, in any form, without prior written consent of Intelligence Press, Inc.
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