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Climate prediction center issues El Niño watch...chance of Big Winter season?


Heat content anomalies (average temperatures in the upper 300m of the ocean) in the equatorial Pacific

There is a 50% chance that El Niño conditions will develop during the second half of 2012

Surf News, 7 June, 2012 :  ENSO-neutral conditions prevailed in May 2012, following the dissipation of La Niña in April. Sea surface temperatures (SSTs) are currently near average across most of the equatorial Pacific Ocean, and above-average in the far eastern Pacific. The Niño 4 and Niño 3.4 indices were near zero during most of May, while the Niño 3 and Niño 1+2 indices remained positive.


The oceanic heat content (average temperature in the upper 300m of the ocean) anomalies became more strongly positive in May, as above-average sub-surface temperatures became established across most of the central and eastern equatorial Pacific. The low-level trade winds and convection over the central equatorial Pacific were near average during May, although convection remained enhanced over portions of the western Pacific. Collectively, these oceanic and atmospheric patterns indicate ENSO-neutral conditions.

 

The extensive volume of above-average sub-surface water temperatures indicates that the tropical Pacific SST anomalies will likely warm further in the coming months. A majority of models predict ENSO-neutral to continue through the June-August (JJA) season. Thereafter, most of the dynamical models predict El Niño to develop during JAS, while the statistical models tend to favor the continuation of ENSO-neutral. Thus, there remains uncertainty as to whether ENSO-neutral or El Niño will prevail during the second half of the year.

The evolving conditions, combined with model forecasts, suggest that ENSO-neutral and El Niño are roughly equally likely during the late northern summer and fall. The CPC/IRI forecast calls for ENSO-neutral conditions through JAS, followed by an approximately 50% likelihood for El Niño during the remainder of the year (see CPC/IRI consensus forecast).

This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA's National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts for the evolution of El Niño/La Niña are updated monthly in the Forecast Forum section of CPC's Climate Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled for 5 July 2012.

www.cpc.ncep.noaa.gov

here's  a great article that makes the things simpler by Dean Luke 

Dean is a former high school pool rat (water polo and swimming teams) and an avid surfer since 1973. His articles have been featured in Surfer Magazine, The Sporting News, and Surfline.com. Lately, his growing interest and involvement has been in local environmental and conservation issues. Dean is a Mililani resident and is the Manager of New Business Development for Oceanic Time Warner Cable. He enjoys taking his three kids surfing and teaching them about the environment. Dean is responsible for OC 250 and 251 and has had a huge impact on surfing's presence in Hawaii and around the world.

El Nino, La Nina, Mucho Confuso!

Amongst the Earth's most broad and influential natural climatic events are the El Nino and La Nina conditions in the Pacific. Everyone's heard of them, but we're not at all exactly sure what they are and how they affect the weather directly over our heads in Hawaii.

I poked around the web for educated details on these two phenomena, but found that a lot of the scientific jargon was way over my head and in some cases, contradictory. Here's how the National Oceanographic and Atmospheric Administration (NOAA) reckons them out; "El Niño and La Nina are phases of naturally occurring climate cycles over the Pacific Ocean and both are large-scale changes in sea-surface temperature across the eastern tropical Pacific. Usually, sea-surface readings off South America's west coast range from the 60s to 70s F, while they exceed 80 degrees F in the "warm pool" located in the central and western Pacific. This warm pool expands to cover the tropics during El Niño, but during La Niña, the easterly trade winds strengthen and cold upwelling along the equator and the West coast of South America intensifies. Sea-surface temperatures along the equator can fall as much as 7 degrees F below normal."

Um, yeah, OK ... I think I understand, but how do they affect the weather (and surf) in the islands? I didn't have complete faith in what I encountered online, so I went in search of a local expert who could provide an explanation in semi-lay terms and in context to Hawaii.

This satellite image illustrates the classic El Nino condition of warm water piling up in the eastern Pacific. Already, storm systems that affect Hawaii are spawned just north of this ocean region and the added surface warmth caused by El Nino adds potential fuel to the fire. (Image: NOAA)
This satellite image illustrates the classic El Nino condition of warm water piling up in the eastern Pacific. Already, storm systems that affect Hawaii are spawned just north of this ocean region and the added surface warmth caused by El Nino adds potential fuel to the fire. (Image: NOAA)

I was fortunate enough to find Roger Lukas, a Professor in the Department of Oceanography at the University of Hawaii. Lukas' faculty profile on the UH School of Ocean and Earth Science Technology (SOEST) site reads as follows; "teaches graduate courses at UH and conducts research in physical oceanography. His areas of research specialization are ocean-atmosphere interaction, seasonal-to-decadal climate variability, tropical ocean dynamics, and the distribution of oceanic water mass properties in the tropics and subtropics. He has been a Principal Investigator on more than 30 research grants by the National Science Foundation, NOAA, and the NASA. Lukas has been Chief Scientist of 14 oceanographic research cruises." Alrighty ... I think I found my man! Below, Roger answered my personal FAQ's about El Nino, La Nina, and Hawaii;

What initiates El Nino and La Nina and can they occur at the same time? El Nino and La Nina cannot occur at the same time; they are the opposite extremes of the El Nino/Southern Oscillation (ENSO) cycle. This cycle varies in its length from about 3-6 years. It is not clear whether it is self-sustaining, or whether it requires energy from some kind of triggering mechanism. Theories are clear about this distinction, but the observations are not.

Are they unique to the Pacific Ocean? Yes, El Nino/La Nina is a tropical Pacific Ocean phenomenon. However, their influence extends poleward from the tropics in both the ocean and atmosphere. The atmospheric response to El Nino in the Pacific does extend to the tropics of the Atlantic Ocean and the Indian Ocean. The Indian Ocean has a similar phenomenon known as the Indian Ocean Dipole, but it is less regular and shorter in duration. It interacts occasionally with the Pacific El Nino.

Is Hawaii currently under either condition now? If not, when was the last time, and when can expect it again? The tropical Pacific is experiencing weak La Nina conditions, which has been influencing the atmospheric circulation over Hawaii, especially this past winter. The next El Nino event has not started yet, and forecast models are mostly predicting "neutral" conditions for the next 6-9 months.

How do both affect hurricane production that puts Hawaii at risk? During El Nino events, there is a greater chance of Hawaii being affected by hurricanes, especially from storms that form near Hawaii. La Nina conditions are less favorable for hurricanes to form in the central Pacific, and cooler ocean temperatures between Hawaii and the eastern tropical Pacific tend to weaken storms that move towards Hawaii from the east.

How is either enhanced or reduced by global warming? This is an area of active research, and there are results supporting both possibilities. In general, the global climate models have somewhat low resolution to properly simulate the ENSO cycle. The models that do simulate ENSO are too computationally expensive to use for projecting climate changes. We need results on this question that are not so sensitive to the models that are used.

How does either affect Hawaii's climatic and surf conditions? Peak El Nino conditions occur during the winter months, and they tend to favor weaker winds and much less rainfall, (providing) great sunny weather for tourists. The storms near the Aleutian Islands are more intense than normal, and perhaps track closer to Hawaii (but without hitting the islands.) Thus, the surf on northern and western shores tends to be significantly larger than during La Nina years. La Nina winters tend to be wetter than average; at least more cloudy as we've seen this year.

Wow, this is really remarkable stuff. As one who's very interested in Earth sciences, the powerful mechanics of nature and the ocean never cease to amaze me. The hurricane information is especially gripping because the two most damaging hurricanes in Hawaii over the last three decades, Iwa (1982) and Iniki (1992), occurred during beefy El Nino conditions. Who knows how or if these storms were influenced by the presence of El Nino? It couldn't have helped the situation, that's for sure.

In Kauai's own version of 9/11, Hurricane Iniki parks itself over the island, causing massive destruction and taking six lives. It is regarded as the most powerful storm ever to hit the islands and it happened in 1992, a very strong El Nino year. (Photo: NOAA)
In Kauai's own version of 9/11, Hurricane Iniki parks itself over the island, causing massive destruction and taking six lives. It is regarded as the most powerful storm ever to hit the islands and it happened in 1992, a very strong El Nino year. (Photo: NOAA)

In Hawaii and other areas in the Pacific, La Nina conditions mean cooler temperatures and more frequent rains over a longer period of time.
In Hawaii and other areas in the Pacific, La Nina conditions mean cooler temperatures and more frequent rains over a longer period of time.

For some, this may just be another pile of useless information, but it definitely bears close monitoring because Hawaii's economy and quality of life has been and will be touched by the alternating presence of El Nino and La Nina periods. Awareness is always a handy thing for people that live in the middle of the big ol' Pacific. Hope this helped!

Thanks to Roger Lukas of the University of Hawaii for his time, expertise, and contribution to this article.

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