What is the La Nina weather pattern?

Answer 1

We are currently in a ENSO-neutral to weak La Niña conditions. Note that La Nina are usually much harder to predict as the general upper jet flow are usually much more amplified. But once they set up, that will make things a little easier.

I can continue to write up a storm on this subject, but I think the following web sites will do a better job at explaining a La Nina Pattern for you. So click on the following links...

http://www.cpc.ncep.noaa.gov/products/outreach/education.shtml

http://www.pmel.noaa.gov/tao/elnino/la-nina-story.html

Answer 2

A La Niña effect may be defined as a drop in average sea-surface temperatures to more than 0.4 degrees C (0.7 degrees F) below normal, lasting at least six months, across a specified part of the eastern tropical Pacific (5 N- 5 S latitude, 120-170 W longitude).

When La Niña forms, the hurricane season is affected as the cooling water creates dramatic changes in the upper-level air currents that play a major role in storm development.

Though El Niño caused worldwide weather problems, it also snuffed out hurricanes. Winds 35,000 to 45,000 feet in the atmosphere shifted to come from the west, basically shearing the tops from developing storms.

During La Niña, high-level westerly winds either weaken or shift to come from the east, allowing more storms to develop, said Jerry Jarrel, director of the National Hurricane Center in Miami.

The 1995 and 1996 hurricane seasons, sandwiching the last La Niña, were the most active back-to-back seasons on record, combining for 20 hurricanes, said Christopher Landsea with the Hurricane Research Division of the National Oceanographic and Atmospheric Administration.

In 1957, 1965 and 1991, El Niños disappeared rapidly without La Niñas forming. However, in 1969, 1972 and 1987, La Niñas were in place by July.

Even if it is too late to affect a hurricane season, La Niña can have a profound impact on fall and winter weather in Florida and the United States. During one, Florida can expect winter - already a dry season - to be warmer and drier.

``It will be drier with fewer cold fronts and more sunshine,'' Landsea said. ``Four or five months with no rain could have a dramatic effect on the potential for fires.''

Some cold fronts still could wander into the state even if temperatures are warmer on average, as expected, Kousky said. ``There will be a lot more variability this winter. Chances are you will experience some colder periods than you had last year.''

The northern part of the country can expect a colder winter, he added, while the Midwest can expect less rain or snow. Droughts struck that region in 1988-89 and 1995-96 following La Niñas.

``It accentuates the normal pattern,'' Kousky said. ``Areas that are cold will be colder. Areas that are warm will be warmer.''

La Niña conditions may persist for as long as two years.

Answer 3

La Nina, the opposite of El Nino, is basically water that is cooler than normal, that is near the equator. It changes weather patterns, and generally affects the entire planet. If you live in the United States, it creates cooler, wetter summers in the west, equal changes in the Midwest and portions of the south, and warmer, drier weather on the eastern half.

Answer 4

The La Nina weather pattern cools the water rather than warms it and occurs less frequently than La Ninos, about every four to seven years.

Answer 5

1. Rise in air pressure over the Indian Ocean, Indonesia, and Australia
2. Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean
3. Trade winds in the south Pacific weaken or head east
4. Warm air rises near Peru, causing rain in the deserts there
5. Warm water spreads from the west Pacific and the Indian Ocean to the east Pacific. It takes the rain with it, causing rainfall in normally dry areas and extensive drought in eastern areas.

Answer 6

la nina is a violent reversal of el nino. it means strong storms and plenty of rain for south-western pacific.