ENSO El Niño / La Niña - Evolução

Luis França

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LA NINA'S BREWING, FORECASTERS WARN

Forecasters warned Tuesday that a La Nina weather pattern - the nasty flip side of El Nino - is brewing, bringing with it the threat of more hurricanes for the Atlantic.

Officials at the National Oceanic and Atmospheric Administration announced the official end of a brief and mild El Nino that started last year. That El Nino was credited with partially shutting down last summer's Atlantic hurricane activity in the midst of what was supposed to be a busy season.

"We're seeing a shift to the La Nina, it's clearly in the data," NOAA Administrator Conrad Lautenbacher said. La Nina, a cooling of the mid-Pacific equatorial region, has not officially begun because it's a process with several months with specific temperature thresholds, but the trend is obvious based on satellite and ocean measurement data, he said.

"It certainly won't be welcome news for those living off the coast right now," Lautenbacher said. But he said that doesn't mean Atlantic seaboard residents should sell their homes.

Forecasters don't know how strong this La Nina will be. However, it typically means more hurricanes in the Atlantic, fewer in the Pacific, less rain and more heat for the already drought-stricken South, and a milder spring and summer in the north, Lautenbacher said. The central plains of the United States tend be drier in the fall during La Ninas, while the Pacific Northwest tends to be wetter in the late fall and early winter.

Of special concern is west Texas which is already in a long-term drought, which during a La Nina will likely get worse, Lautenbacher said.

*SNIP*

http://apnews.myway.com/article/20070228/D8NID1IO1.html


Boas,

Coloquem aqui todos os comentários sobre o fenómeno, pq acho que vai ser muito discutido este ano...;) :D

Movi o teu Post para aqui para melhor enquadramento e correcção do nome do Tópico e juntei o meu e o teu post;)

Moderador Meteopt
 
Editado por um moderador:

Seringador

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Re: La Niña - Previsão NOAA - 2007

Bem

Isso são boas notícias para convergir com a minha previsão para este ano, de um uma primavera e verão amenos, e La Niña consegue ser imprevisível e mais fria como consequências a Norte e mais quente e seca a Sul, portanto já sabem se isto se vier a confirmar teremos temperaturas quentes e fora de época por ex: no Brasil e África e ao mesmo tempo frio e precipitação a norte, pq vai influenciar directamente quer o comportamento do PAN, quer e sobretudo o ENSO depois da ciclogénese no Atlântico principalmente a partir do Fim do Verão


podendo arriscarnos a ter um anos como 2000 ou 1991, que lá para o fim brindou com um manto branco toda a Europa

podem tirar algumas dúvidas aqui neste site, que podem guardar nos favoritos, pq acho que vai ser útil este ano

http://www.elnino.noaa.gov/lanina.html
 

kimcarvalho

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Re: La Niña - Previsão NOAA - 2007

Bem

Isso são boas notícias para convergir com a minha previsão para este ano, de um uma primavera e verão amenos, e La Niña consegue ser imprevisível e mais fria como consequências a Norte e mais quente e seca a Sul, portanto já sabem se isto se vier a confirmar teremos temperaturas quentes e fora de época por ex: no Brasil e África e ao mesmo tempo frio e precipitação a norte, pq vai influenciar directamente quer o comportamento do PAN, quer e sobretudo o ENSO depois da ciclogénese no Atlântico principalmente a partir do Fim do Verão


podendo arriscarnos a ter um anos como 2000 ou 1991, que lá para o fim brindou com um manto branco toda a Europa

podem tirar algumas dúvidas aqui neste site, que podem guardar nos favoritos, pq acho que vai ser útil este ano

http://www.elnino.noaa.gov/lanina.html

Site guardado! :thumbsup:

E quem sabe este ano não apareça alguma surpresa tipo Austrália e neve algures na Europa em pleno Verão... :rolleyes:
 

Luis França

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Re: La Niña - Previsão NOAA - 2007

New evidence that global warming fuels stronger Atlantic hurricanes
http://www.physorg.com/news91900409.html

newevidencet.jpg
 

Mário Barros

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Re: La Niña - Previsão NOAA - 2007

La Nina may form in Pacific by May as El Nino disappears
http://news.yahoo.com/s/nm/20070308/sc_nm/weather_nina_dc;_ylt=Ah3gmOuHJnEA13TwYjqAnj4PLBIF

NEW YORK (Reuters) - The La Nina weather anomaly may form in the equatorial Pacific in the next two to three months, possibly increasing the risks for more hurricanes later this year in the Atlantic.

Espetaculo mais furacões este ano é bom bom bom bom venha ela :rain: :rain: :rain: :rain: com ele(s).
 

Vince

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Re: ENSO El Niño / La Niña (Evolução)

Parece que é desta que teremos a La Ninã:



La Niña conditions will further develop during the next 3 months.
During August 2007, negative sea surface temperature (SST) anomalies in the eastern equatorial Pacific expanded westward, and now extend from the coast of South America to the date line (180ºW) (Fig. 1). Consistent with this additional cooling, three of the Niño indices remained cooler than −0.5 ºC throughout August, with only Niño 4 remaining average (latest weekly values: Niño 1+2 (−2.3ºC), Niño 3 (−1.2ºC), Niño 3.4 (−0.6ºC), Niño 4 (+0.0ºC)) (Fig. 2). The upper-ocean heat content (average temperatures in the upper 300 m of the ocean) in the central and east-central equatorial Pacific continued to be below average (Fig. 3), with temperatures at thermocline depth ranging from 1°C to 3°C below average (Fig. 4). While not as pronounced as in previous months, the low-level easterly winds remained stronger than average in the west-central equatorial Pacific, convection was suppressed throughout the central and eastern equatorial Pacific, and an area of slightly enhanced convection again covered parts of Indonesia and the far western Pacific. Collectively, the oceanic and atmospheric conditions reflect La Niña conditions.
The recent SST forecasts for the Niño 3.4 region range from ENSO-neutral to La Niña (Fig. 5). Nearly all of the dynamical ENSO models forecast the continuing development of La Niña during the next couple of months, and several of the statistical models also indicate the continuation of La Niña conditions through the end of the year. Therefore, current atmospheric conditions (stronger than average easterlies over the west-central Pacific) and observed oceanic trends indicate that La Niña conditions will further develop and possibly strengthen during the next 3 months.
Based on current conditions in the tropical Pacific, the most recent model outlooks, and on results from historical studies on the effects of cold episodes, wetter than normal conditions are expected over Indonesia and drier than normal conditions are anticipated over the central equatorial Pacific during September - November. During this period, potential impacts over the contiguous United States include wetter than normal conditions over the Pacific Northwest and drier than normal conditions over the southwestern states.

(c) Fonte: El Niño/Southern Oscillation (ENSO) Diagnostic Discussion
 

Vince

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A La Niña está já bem confirmada no Pacífico, e intensifica-se.
Os modelos prevêm que dure até à Primavera de 2008 (Outono no Hemisfério Sul).

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION 8 November 2007
La Niña continued to strengthen during October 2007, as equatorial sea surface temperature (SST) anomalies became increasingly negative from 170oE to the South American coast (Fig. 1). The latest 4-week analysis shows the largest SST departures (-2ºC to -3ºC) located between 140oW and the South American coast, with departures of -0.5oC to -1oC observed near the Date Line (Fig. 2). All of the Niño region indices, except for Niño-4, remained lower than -1.0oC (Fig. 3) indicating that La Niña is approaching moderate-strength (3-month running mean value of the Niño 3.4 index below -1.0oC).
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html

ENSO Wrap-Up
A regular commentary on the El Nino-Southern Oscillation
CURRENT STATUS as at 14th November 2007

La Niña event is well established in the Pacific, with further intensification evident during the past three weeks. The main characteristics of the event are colder than average temperatures along the equator both on and below the surface, stronger than average Trade Winds and reduced cloudiness. The Southern Oscillation Index (SOI) is the one ENSO indicator that is yet to show a typical La Niña signal: it remains neutral at about +6 for the past 30 days. Computer models forecast the La Niña to last until at least until the southern autumn of 2008.
http://www.bom.gov.au/climate/enso/
 

Vince

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Mais uma actualização:

EL NIÑO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION
issued by CLIMATE PREDICTION CENTER/NCEP
6 December 2007


Synopsis: La Niña is expected to continue into Northern Hemisphere spring 2008.

La Niña reached moderate strength during November 2007, with below-average sea surface temperatures (SSTs) extending from 160E to the South American coast (Fig. 1). All of the Niño region indices remained cooler than 1.0oC (Fig. 2), with the most substantial cooling occurring in the Niño-4 region located in the central equatorial Pacific Ocean (150W-160E and 5N-5S). The upper-ocean heat content (average temperatures in the upper 300 m of the ocean) in the central and east-central equatorial Pacific remained below average (Fig.3), with temperatures ranging from 2oC to 5oC below average at thermocline depth (Fig. 4). Consistent with these oceanic conditions, low-level easterly winds and upper-level westerly winds strengthened across the central equatorial Pacific, convection remained suppressed throughout the central and eastern equatorial Pacific, and an area of enhanced convection covered the far western Pacific. Collectively, these oceanic and atmospheric conditions reflect La Niña.

The recent SST forecasts (dynamical and statistical models) for the Niño 3.4 region indicate a continuation of La Niña into Northern Hemisphere spring 2008 (Fig. 5). Over half of the models indicate a moderate-to-strong La Niña through February, followed by a gradual weakening thereafter. Current atmospheric and oceanic conditions and recent trends are consistent with the model forecasts.

Expected La Niña impacts during December-February include a continuation of above-average precipitation over Indonesia and below-average precipitation over the central and eastern equatorial Pacific. For the contiguous United States, potential impacts include above-average precipitation in the Northern Rockies, the Pacific Northwest, the Ohio and Tennessee Valleys, and parts of the Great Lakes region. Below-average precipitation is expected across the South, particularly in the southwestern and southeastern states.
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html
 

Rog

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As condições de La Niña continuam presentes, embora nas ultimas semanas a anomalia negativa tenha sido menor e tinha enfraquecido o fenómeno La niña.
Ainda assim, devido à extenção de aguas com anomalia negativa é provável que se mantenha até meados deste ano com moderada intensidade. é provável que nos ultimos 4 a 5 meses do ano, o ENSO estaja com valores neutros.
alguns gráficos:

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Fonte