Furacão ALEX (Atlântico 2016 #AL01)
- Thread starter Felipe Freitas
- Data de início
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luismeteo3
Furacão
Ciclone tropical Alex deve atingir Açores na noite de quinta-feira - IPMA
- O Instituto Português do Mar e da Atmosfera (IPMA) informou hoje que o ciclone tropical Alex deve atingir os Açores no final do dia de quinta-feira, situação que pode originar fenómenos extremos de chuva, vento e agitação marítima. http://24.sapo.pt/article/lusa-sapo...ushdown&_swa_csource=sapo.pt&_swa_cmedium=web
Norther
Cumulonimbus
belo olho que se formou no Alex 
http://www.meteogalicia.es/datosred...nthly/Day 14/webexterna_ColorIR87_[08-45].jpg
http://www.meteogalicia.es/datosred...nthly/Day 14/webexterna_ColorIR87_[08-45].jpg
Todo o acompanhamento do Alex foi feito no tópico das ilhas:
Início:
http://www.meteopt.com/forum/topico/seguimento-acores-e-madeira-janeiro-2016.8549/page-7
Fim:
http://www.meteopt.com/forum/topico/seguimento-acores-e-madeira-janeiro-2016.8549/page-40
Início:
http://www.meteopt.com/forum/topico/seguimento-acores-e-madeira-janeiro-2016.8549/page-7
Fim:
http://www.meteopt.com/forum/topico/seguimento-acores-e-madeira-janeiro-2016.8549/page-40
Duarte Sousa
Moderação
3 vídeos de imagens de satélite retiradas do site do IPMA do Furacão Alex durante o dia de ontem.
Alex formed over the Atlantic on 14 January, a very early date for an Atlantic hurricane.
http://www.eumetsat.int/website/home/Images/ImageLibrary/DAT_2897599.html
http://www.eumetsat.int/website/home/Images/ImageLibrary/DAT_2897599.html
Dias Miguel
Cumulonimbus
http://edition.cnn.com/2016/01/15/world/hurricane-alex-atlantic/index.html
Bastante interessante a análise da CNN acerca das razões para a formação do Furação Alex. Segundo o que entendi, a diferença entre a temperatura da água do mar (aprox. 20ºC) e a temperatura do ar a níveis altos da atmosfera ( aprox. - 42ºC) proporcionaram energia ao Alex para evoluir de tempestade tropical para furação...
Bastante interessante a análise da CNN acerca das razões para a formação do Furação Alex. Segundo o que entendi, a diferença entre a temperatura da água do mar (aprox. 20ºC) e a temperatura do ar a níveis altos da atmosfera ( aprox. - 42ºC) proporcionaram energia ao Alex para evoluir de tempestade tropical para furação...
É possível rastrear a origem meteorológica do Alex até ao Pacífico tropical 
Excelente artigo
An Atlantic hurricane in January
MODIS Band 3–6–7 satellite image January 14, 2015 NASA WORLDVIEW
Alex was a very unusual storm…
And it had a very interesting history! In fact, it was quite a saga, with a plot twist of a prequel.
We’ll come back to that; the storm itself started with this feature on satellite imagery which caught my eye on January 6, indicative of rapid non-tropical storm development, in this case bombogenesis.
January 6, 2016
By the next day, it had a vivid appearance on water vapor satellite imagery.
January 7, 2016 NASA Earth Science Office
Alex-to-be progressed slowly across the Atlantic, and a few days later began taking on characteristics of a subtropical cyclone, in which convection (showers/thunderstorms) becomes more concentrated around the center, the system loses its fronts, and the core of the storm becomes warmer than its surroundings.
January 11, 2016 UW-Madison SSEC RealEarth
Finally a couple days after that it was officially named Subtropical Storm Alex.
Then the following day, January 14, it became a hurricane. The difference between a tropical cyclone such as that and a subtropical one is that the former has a deeper warm core and its strongest winds closer to the center of circulation.
Hurricane Alex January 14, 2016 UW-Madison SSEC CIMSS
On the 15th: landfall of a tropical cyclone, in the Azores, in January.
The curious case of Alex was not over, though, as strong ridging of high pressure aloft to the north helped steer the ex-hurricane.
Strong ridging of high pressure aloft (red) to the north which contributed to the steering of Alex and its remnant
As two more non-tropical cyclones, the first being another meteorological bomb, developed near the East Coast, Alex’s remnant spin was forced back westward to near the southern tip of Greenland and then to Newfoundland and Labrador! (And what’s more, models are predicting the combo of what was left of Alex and a system which absorbed it to rotate back down to New England.)
Low-level spin January 12-17, 2016 showing the red blob with Hurricane Alex and its remnant retrograding from the Azores to Canada. UW-Madison SSEC CIMSS
But that’s not all — per the graphic below the origin of what would become a hurricane a week and a half later can be traced all the way back to a pulse in the subtropical jet stream (STJ) which came from the tropical Pacific Ocean!
Enhancement of the STJ and southern branch of the main polar jet stream, as was the case at the time in early January, is characteristic of El Niño and its warmer-than-average water in the central and eastern equatorial Pacific. While not the only cause, could El Niño, which as I highlighted in my recent article is often misunderstood, and whose conventional wisdom is that it’s an inhibiting factor to Atlantic tropical cyclones, actually have helped lead to this rare January hurricane?
NERC Satellite Receiving Station, Dundee University, Scotland
Excelente artigo
An Atlantic hurricane in January
MODIS Band 3–6–7 satellite image January 14, 2015 NASA WORLDVIEW
Alex was a very unusual storm…
And it had a very interesting history! In fact, it was quite a saga, with a plot twist of a prequel.
We’ll come back to that; the storm itself started with this feature on satellite imagery which caught my eye on January 6, indicative of rapid non-tropical storm development, in this case bombogenesis.
January 6, 2016
By the next day, it had a vivid appearance on water vapor satellite imagery.
January 7, 2016 NASA Earth Science Office
Alex-to-be progressed slowly across the Atlantic, and a few days later began taking on characteristics of a subtropical cyclone, in which convection (showers/thunderstorms) becomes more concentrated around the center, the system loses its fronts, and the core of the storm becomes warmer than its surroundings.
January 11, 2016 UW-Madison SSEC RealEarth
Finally a couple days after that it was officially named Subtropical Storm Alex.
Then the following day, January 14, it became a hurricane. The difference between a tropical cyclone such as that and a subtropical one is that the former has a deeper warm core and its strongest winds closer to the center of circulation.
Hurricane Alex January 14, 2016 UW-Madison SSEC CIMSS
On the 15th: landfall of a tropical cyclone, in the Azores, in January.
The curious case of Alex was not over, though, as strong ridging of high pressure aloft to the north helped steer the ex-hurricane.
Strong ridging of high pressure aloft (red) to the north which contributed to the steering of Alex and its remnant
As two more non-tropical cyclones, the first being another meteorological bomb, developed near the East Coast, Alex’s remnant spin was forced back westward to near the southern tip of Greenland and then to Newfoundland and Labrador! (And what’s more, models are predicting the combo of what was left of Alex and a system which absorbed it to rotate back down to New England.)
Low-level spin January 12-17, 2016 showing the red blob with Hurricane Alex and its remnant retrograding from the Azores to Canada. UW-Madison SSEC CIMSS
But that’s not all — per the graphic below the origin of what would become a hurricane a week and a half later can be traced all the way back to a pulse in the subtropical jet stream (STJ) which came from the tropical Pacific Ocean!
Enhancement of the STJ and southern branch of the main polar jet stream, as was the case at the time in early January, is characteristic of El Niño and its warmer-than-average water in the central and eastern equatorial Pacific. While not the only cause, could El Niño, which as I highlighted in my recent article is often misunderstood, and whose conventional wisdom is that it’s an inhibiting factor to Atlantic tropical cyclones, actually have helped lead to this rare January hurricane?
NERC Satellite Receiving Station, Dundee University, Scotland
Furacão Alex 
E um exemplo de trovoada:
Não é de todo um radar mas é possível fazer umas inferências engraçadas enquanto não se tiver acesso a ele
E um exemplo de trovoada:
Não é de todo um radar mas é possível fazer umas inferências engraçadas enquanto não se tiver acesso a ele
Levando à letra, a Terceira foi afetada por uma tempestade tropical e não um furacão.
Na altura parecia óbvio, mas como expliquei nesse dia, havia boas razões para manter o estatuto de furacão enquanto não acabasse de passar pelas ilhas:
De qualquer forma esse assunto ainda não está inteiramente fechado.
É bastante provável que o Alex tenha deixado de ter ventos de furacão umas quantas horas antes. A partir do momento que a parede do olho rebentou ontem à noite não voltou a recuperar e isso deve ter enfraquecido bastante os ventos, por outro lado expandiu-os mais um bocado.
A manutenção de status de furacão deve ter tido a ver com:
- o começo da transição extra-tropical em que processos baroclínicos podem intensificar a depressão compensando o enfraquecimento dos processos barotrópicos (convecção profunda, etc)
- a inexistência de dados reais. O Atlântico é uma imensidão onde praticamente poucas sondagens se fazem para injectar nos modelos. Nos ciclones tropicais do Atlântico isso é compensado com os voos RECON, em que há dois tipos de missões, umas de muita altitude em que no possível trajecto dum ciclone são lançadas dezenas de sondas a medir a atmosfera numa área enorme, e outras de baixa altitude atravessando múltiplas vezes o ciclone para medir em tempo real a situação real do mesmo. Esses dados além de servirem para avaliar a situação, são depois injectados em modelos melhorando as previsões destes. Nisto tudo por vezes chegam a ser feitas muitas centenas de sondagens em apenas um ciclone.
Mas nesta região dos Açores isso não acontece, as missões RECON não vem para estes lados.
Tive esperanças que fizessem uma missão excepcional, fartei-me de ver o feed das missões a ver se aparecia alguma coisa, mas nada. Tinha esperança porque seria muito importante até para obter dados para ciência, dada a raridade do ciclone.
Houve uma vez que próximo dos Açores não houve os habituais voos da NOAA e da USAF, mas a NASA mandou um drone para efeitos científicos. Desta vez não, mas também ninguém estava à espera dum furacão em Janeiro
http://www.meteopt.com/forum/topico...-atlantico-2012-al14.6686/page-20#post-342017
- é muito raro na véspera de um landfall diminuir-se avisos, isso é perigoso e contraproducente, e caso as coisas corram mal, haveria consequências chatas. Um dispositivo é activado, e depois na véspera não se pode estar a diminuir a prevenção.
De qualquer forma esse assunto ainda não está inteiramente fechado.