No, The historical record reveals many back-to-back events. Some prolonged cold episodes during the past 50 years are: 1983-85, 1973-76, 1954-56 and 1949-51.

La Niña is defined as cooler than normal sea-surface temperatures in the central and eastern tropical Pacific ocean that impact global weather patterns. La Niña conditions recur every few years and can persist for as long as two years.

El Niño and La Niña are extreme phases of a naturally occurring climate cycle referred to as El Niño/Southern Oscillation. Both terms refer to 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.

El Niño and La Niña result from interaction between the surface of the ocean and the atmosphere in the tropical Pacific. Changes in the ocean impact the atmosphere and climate patterns around the globe. In turn, changes in the atmosphere impact the ocean temperatures and currents. The system oscillates between warm (El Niño) to neutral (or cold La Niña) conditions with an on average every 3-4 years.

Both El Niño and La Niña impact global and U.S. climate patterns. In many locations, especially in the tropics, La Niña (or cold episodes) produces the opposite climate variations from El Niño. For instance, parts of Australia and Indonesia are prone to drought during El Niño, but are typically wetter than normal during La Niña.

La Niña often features drier than normal conditions in the Southwest in late summer through the subsequent winter. Drier than normal conditions also typically occur in the Central Plains in the fall and in the Southeast in the winter. In contrast, the Pacific Northwest is more likely to be wetter than normal in the late fall and early winter with the presence of a well-established La Niña.

El Niño and La Niña occur on average every 3 to 5 years. However, in the historical record the interval between events has varied from 2 to 7 years. According to the National Centers for Environmental Prediction, this century's previous La Niñas began in 1903, 1906, 1909, 1916, 1924, 1928, 1938, 1950, 1954, 1964, 1970, 1973, 1975, 1988, and 1995. These events typically continued into the following spring.

The jury is still out on this. Are we likely to see more El Niños because of global warming? Will they be more intense? These are the main research questions facing the science community today. Research will help us separate the natural climate variability from any trends due to man's activities. We cannot figure out the "fingerprint" of global warming if we cannot sort out what the natural variability does.

La Niña refers to a period when ocean temperatures across the central and eastern tropical Pacific Ocean are cooler than normal.

Scientists from NOAA and other agencies use a variety of tools and techniques to monitor and forecast changes in the Pacific Ocean and the impact of those changes on global weather patterns. In the tropical Pacific Ocean, El Niño is detected by many methods, including satellites, moored buoys, drifting buoys, sea level analysis, and expendable buoys.

Since a strong jet stream is an important ingredient for severe weather, the position of the jet stream determines the regions more likely to experience tornadoes. Contrasting El Niño and La Niña winters, the jet stream over the United States is considerably different. During El Niño the jet stream is oriented from west to east over the northern Gulf of Mexico and northern Florida. Thus this region is most susceptible to severe weather.

The La Niña episodes can be categorized according to the combined strength, location and coverage of the cold ocean waters. Moderate-to-strong La Niña episodes impact the weather patterns in a very similar manner, and thus, this distinction is thought by many to have little meaning. The weather patterns with a weak La Niña episode tend to be somewhere in between those of a stronger episode and those of near-neutral conditions.

Dr. William Gray at the Colorado State University has pioneered research efforts leading to the discovery of La Niña impacts on Atlantic hurricane activity, and to the first and, presently only, operational long-range forecasts of Atlantic basin hurricane activity. According to this research, the chances for the continental U.S. and the Caribbean Islands to experience hurricane activity increases substantially during La Niña.

The cooling of the ocean waters leads to changes in the patterns of tropical rainfall from Indonesia to South America (a distance of more than one-half the circumference of the earth), which significantly affects the strength and location of the atmospheric jet stream over the eastern North Pacific and North America. These changes in the jet stream alter the weather patterns. There will likely be many similarities between the two winters, and there will also be some differences.

No, it is very typical to other La Niña episodes that we have observed during the past 50 years.

There's no question that La Niña continues to contribute to the tropical Atlantic weather that we are experiencing. But remember, La Niña is only one of the climate elements that can produce an above average tropical storm and hurricane season in the North Atlantic. The ongoing pattern of tropical rainfall features above-normal rains across Indonesia and the eastern Indian Ocean, and a near-absence of rainfall across the central and eastern equatorial Pacific.

It is inaccurate to label individual storms or events as a La Niña or El Niño event. Rather, these climate extremes affect the position and intensity of the jet streams, which in turn affect the intensity and track of storms. During La Niña, the normal climate patterns are enhanced. For example, in areas that would normally experience a wet winter, conditions would likely be wetter than normal.

There have only been two strong La Niña events. Although scientists have looked for a correlation between La Niña and tornadoes, there just isn't enough data to make any conclusions.

This question does not have a simple or straightforward answer, since this is not a settled issue. Fundamentally we are not exactly sure why the Pacific should have an El Niño/La Niña cycle and the Atlantic not. We observe that this is the case and can think of reasons why this makes sense, but if we had no observations to tell us the answer in advance I don't think we would deduce it from theory.

No! It is wrong to think of this as an oscillation, simply swinging back and forth. There can be several El Niños in a row, as we had in the early 1990s. Many scientists are coming to the view that there may not be such a thing as La Niña, or at least that it is not just the opposite of El Niño. Perhaps there is just the normal situation that is disturbed every few years by an El Niño.

Recent studies have indicated that JDMS occurs at a rate of about 3 per million children (under 18 years old) per year in the United States. That rate leads to approximately 300-400 new cases diagnosed per year in the US. By comparison, JRA (Juvenile Rheumatic Arthritis), which is considered a rare disease, has an incidence approximately 10 times higher.

Actually, it isn't. The National Organization of Rare Disorders (NORD) states that "a rare disease is one which affects fewer than 200,000 people in the US." There are less than 5000 rare disorders. Among the rare disorders you may have heard of are: ulcerative colitis, carpal tunnel syndrome and multiple sclerosis.

LA FEAT is Los Angeles Families for Effective Autism Treatment. LA FEAT was founded by parents of autistic children. LA FEAT is a non-profit, 501(c)3 organization for parents and families of children with autism. We have a board of directors of parents of children with autism. We serve families in greater Los Angeles and the surrounding counties.

Rare diseases and disorders are those which affect small patient populations, defined as fewer than 200,000 individuals in the United States. Taken together 25,000,000 Americans suffer from one of 6,000 rare diseases or disorders. Rheumatic disease represents more that 100 different diseases that are chronic and unpredictable. More than 40 million Americans, or one in six, have a rheumatic disease, including more than 285,000 children.

Around 50 million people in the world have epilepsy, or about 1% of the population. It is the most common serious neurological condition.

Its very rarity makes this question hard to answer. One study (Rosenberg 1985) of 1,500 muscle biopsy specimens found TAs in 1.0%. Another study (Niakan 1985) of 3,000 muscle biopsies detected TAs in 0.6%. These specimens were from folk with suspected muscle disease so they were already a small minority of the general population and of course not all of those with TAs have TAM. A study of children under the age of 15 in western Sweden disclosed only 1 child with TAM in a 15 year period.