Climate Phase Forecast
Updated: December 4, 2008
The Pacific Ocean has been in Neutral conditions for the past 8 months and will likely remain neutral through the winter of 2008/2009.
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Current East Pacific SST Analysis |
Current East Pacific SST Anomaly Analysis |
Sea surface temperatures along the equator in the eastern and central Pacific Ocean have been close to normal since April of 2008. Near normal sea surface temperatures in this area of the Pacific is known as Neutral conditions. Historically, neutral conditions occur roughly half the time. At other times, this area of the Pacific can swing into periods where it is much warmer than normal, known as El Niño, or much colder than normal, referred to as La Niña. The Pacific Ocean was in a fairly strong La Niña last winter and spring.
Neutral conditions are expected to continue through the winter of 2008/2009 and possibly longer. However, the atmosphere over the Pacific is giving mixed signals. The Southern Oscillation Index, which is a difference in surface barometric pressure between the central and western Pacific, is strongly positive at this time and more consistent with La Niña. Additionally, the easterly trade winds over the central Pacific have been consistently stronger than normal which could lead to a cooling of Ocean temperatures. On the other hand, weather patterns over the Southeast U.S. have been colder than normal with frequent cold front passage which is very uncharacteristic of La Niña conditions. This all means there may be a chance that we slip back into La Niña sometime this winter, but that is not a high likelihood. There is almost no chance of El Niño developing.
What does Neutral conditions in the Pacific mean for our climate over the winter months? Without a well-defined El Niño or La Niña in the Pacific, there is no indication that temperatures or rainfall will be either above normal or below normal. More variable weather is common in neutral winters, with periods of very cold weather mixed in with warm spells. Severe freezes that can impact citrus and other winter crops are more likely this year. Near-normal rainfall is the best forecast, as there is no El Niño or La Niña to tip the balance towards wetter or drier. For more information on climate impacts in the Southeast, see the latest climate outlook.
The SECC tracks the temperatures of the Pacific Ocean using the JMA index. For more information and current JMA values, see the following link:
Other El Niño/La Niña Forecasts
Below are links to El Niño/La Niña forecasts from other centers in the U.S. and worldwide. Caution: the SECC may not agree with their forecasts and/or classification criteria.