Furacão FRED (Atlântico 2015 #AL06)

Afgdr

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A Tempestade Tropical Fred desloca-se para WNW com ventos máximos sustentados de 40 milhas por hora.

Nas próximas horas, deverá enfraquecer e tornar-se depressão tropical. Depois de se tornar pós-tropical/remnant low, parece que as condições poderão ser favoráveis a um novo desenvolvimento do sistema.

Previsão do NHC
000
WTNT41 KNHC 031434
TCDAT1

TROPICAL STORM FRED DISCUSSION NUMBER 19
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015
1100 AM AST THU SEP 03 2015

As anticipated, a surge of strong upper-level westerly winds removed
most of the convection from Fred overnight, and again the cyclone
consists of a very vigorous swirl of low clouds. Just like
yesterday, a few new convective cells are redeveloping to the north
of the center. Assuming that the winds are gradually decaying, the
initial intensity has been lowered to 35 kt. The strong upper-level
winds affecting Fred are forecast to continue creating a very
hostile environment for the cyclone. Consequently, the NHC forecast
calls for Fred to become a remnant low in about 12 to 24 hours. By
the end of the forecast period, if Fred has not dissipated, models
are showing less shear. This combined with the presence of anomalous
warm waters in the North Atlantic, will provide a small opportunity
for Fred to redevelop some as indicated in the NHC forecast.

A weak to moderate ridge of high pressure over the North Atlantic
is steering Fred toward the west-northwest or 295 degrees at 9 kt.
In a couple of days, Fred or its remnants will be located on the
southwestern edge of the ridge, and will begin to move toward the
northwest and north. After 3 days, the system will then recurve
toward the northeast around the ridge. Although most of the track
models provided this solution, the NHC forecast is very close to the
consensus of the GFS and the ECMWF global models.

FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 21.5N 34.1W 35 KT 40 MPH
12H 04/0000Z 21.9N 35.3W 30 KT 35 MPH
24H 04/1200Z 22.3N 37.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 05/0000Z 22.6N 38.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 05/1200Z 23.0N 40.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 06/1200Z 25.0N 42.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 07/1200Z 27.5N 41.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 08/1200Z 30.5N 38.5W 30 KT 35 MPH...TROPICAL DEPRESSION

$$
Forecaster Avila


17H45 UTC (NOAA)

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19h23 UTC (Wunderground)

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Previsão de rota (NHC)

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Alguns modelos colocam Fred a atravessar os Açores.

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Dias Miguel

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É impressão minha ou o Fred irá trazer surpresas para a próxima semana :shocking:
À primeira vista, as trajectórias de outra depressão tropical que tenha surgido perto de Cabo Verde que se assemelha à previsão do Fred ´são as que afectaram directamente os Açores e uma delas atingiu o continente como depressão pós-tropical (Furação Jeanne em 1998)

Hurricane Jeanne
Category 2 hurricane (SSHWS)

Duration September 21 – October 1
Peak intensity 105 mph (165 km/h) (1-min) 969 mbar (hPa)
Between September 19 and September 20, a slow-moving tropical wave crossed the west coast of Africa. By the following day, an increase in deep convection allowed it to be classified as Tropical Depression Ten. Forming about 160 miles (260 km) west of Guinea-Bissau, it was the easternmost tropical cyclone development in the Atlantic basin since Tropical Storm Christine in 1973. Due to light wind shear, the depression strengthened into Tropical Storm Jeanne by 1800 UTC on September 21. Further significant intensification occurred and Jeanne became a hurricane about 24 hours later. Late on September 23, the storm became a Category 2 hurricane on the Saffir–Simpson Hurricane Wind Scale. At 1800 UTC on September 24, Jeanne attained its peak intensity with maximum sustained winds of 105 mph (170 km/h) and a minimum barometric pressure of 969 mbar (28.6 inHg).[56]

After peaking as a moderate Category 2 hurricane, an increase in vertical wind shear slowly weakened the storm. Around that time, Jeanne began curving northwestward. By late on September 25, the storm was downgraded back to a Category 1 hurricane. Three days later, a trough forced Jeanne to accelerate toward the north-northeast. It re-strengthened slightly on September 28, though the storm began weakening again. Late on September 29, Jeanne was downgraded to a tropical storm. Shortly before weakening further to a tropical depression on October 1, a wind gust of 40 mph (64 km/h) was reported on Horta in the Azores. The storm then passed through the Azores, but lost tropical characteristics by 1200 UTC on October 1. The remnant extratropical cyclone struck Portugal on October 4 and became unidentifiable over Spain later that day.[56]
 

Thomar

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Na última actualização do http://www.nhc.noaa.gov/ existe a possibilidade de a depressão (Fred)
aumentar de intensidade para tempestade Tropical (extra-tropical),
na segunda feira, chegando aos Açores na quarta-feira madrugada/manhã como tempestade.
Ainda faltam muitos dias, mas pela via das dúvidas é melhor ir acompanhando.
 

Vince

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No aviso da madrugada passou a Tempestade tropical de novo, devido a uma leitura ASCAT


TROPICAL STORM FRED DISCUSSION NUMBER 25
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015
1100 PM AST FRI SEP 04 2015

An ASCAT-A pass just before 0000 UTC showed a small area of 35-kt
winds northeast of Fred's center, and that is the basis for the

initial intensity, making Fred a tropical storm once again. The
central pressure has been adjusted upward to 1009 mb based on
observations from drifting buoy 13519, as it appears Fred is now
embedded in an environment of higher pressure. Despite rather
hostile vertical shear, Fred has managed to maintain enough
organized deep convection during the past couple of days to stave
off post-tropical status. The latest burst of convection is now
moving away from the low-level center, but this bursting pattern
seems likely to continue for the next couple of days as the cyclone
moves over gradually warmer waters in moderate to strong shear.
Since Fred has survived this long, it seems less likely that the
cyclone will become post-tropical in the short term
, and that is no
longer shown in the official forecast.
However, given our limited
ability to predict convective scale changes, this still remains a
possibility.






No último aviso de há pouco, previsto enfraquecer mas até voltar a intensificar-se um pouco mais tarde.
Mas é uma previsão muito incerta como podem ler na disussion


TROPICAL STORM FRED DISCUSSION NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015
500 AM AST SAT SEP 05 2015

Fred continues to produce bursts of convection, although the bursts
are smaller and farther from the center than they were 24 hours
ago. This suggests that the ongoing 35-40 kt of westerly vertical
shear is causing a gradual weakening. The initial intensity remains
35 kt based on a subjective satellite intensity estimate from TAFB,
as well as objective AMSU and satellite consensus estimates from
CIMSS and CIRA. The central pressure has been lowered a little
based on additional observations from drifting buoy 13519, which
reported a minimum pressure of 1008.4 mb as the center of Fred
passed to the north.

The initial motion is 290/10. Fred is approaching a large break in
the subtropical ridge caused by a mid- to upper-level trough and
associated surface low centered several hundred miles east of
Bermuda. The track guidance is in good agreement that this
baroclinic system will move eastward for the next several days, with
Fred recurving to the northeast between it and the subtropical
ridge. After recurvature, there is some spread in the forecast
forward speed, with the new track compromising between the faster
ECMWF/GFS models and the slower UKMET/Canadian models. The new
track is nudged slightly to the north of the previous track from
36-96 hours, and then is nudged a little to the east of the previous
track at 120 hours.

The intensity forecast is low in confidence due to several possible
scenarios. First, although it is not explicitly forecast, Fred
could become a remnant low at any time during the next 24 to 36
hours due to continued shear and dry air entrainment, followed by
regeneration to a tropical cyclone when the shear subsequently
decreases. Second, the dynamical models have two scenarios for Fred
as it interacts with the above-mentioned trough and surface low
after recurvature. One possibility, supported by the GFS and the
ECMWF, is that a relatively weak Fred gets absorbed into the
baroclinic low and dissipates earlier than currently forecast.
Another possibility, supported by the UKMET and Canadian models, is
that Fred stays farther away from the baroclinic low and intensifies
more than is currently forecast. Given the uncertainty, the new
intensity forecast is similar to the previous forecast in calling
for slight weakening early in the forecast period followed by slight
intensification after 36 hours.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 23.2N 41.0W 35 KT 40 MPH
12H 05/1800Z 23.7N 42.1W 30 KT 35 MPH
24H 06/0600Z 24.7N 42.7W 30 KT 35 MPH
36H 06/1800Z 26.3N 42.5W 30 KT 35 MPH
48H 07/0600Z 28.2N 41.1W 35 KT 40 MPH
72H 08/0600Z 31.5N 37.5W 35 KT 40 MPH
96H 09/0600Z 35.0N 33.0W 35 KT 40 MPH
120H 10/0600Z 36.5N 30.0W 35 KT 40 MPH
 

Vince

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Agora vai andar 2 dias em que a água não é extremamente quente, mas também não é nada má para um ciclone tropical.

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E depois vai entrar numa região aonde não tem faltado humidade e instabilidade na última semana.

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Pelo que é bem possível que o Fred sobreviva até aos Açores, ou imediações.
Agora saber com que estrutura, natureza (tropical ou não, absorvido, etc) ou intensidade é que já é muito imprevisível. O mais provável é não ser nada de especial, mas temos que ir acompanhando.


Mantém-se a produzir fortes trovoadas embora de forma pulsante

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Vince

Furacão
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O Fred passou boa parte do dia "despido" de convecção, péssimo sinal, mas a circulação tem-se aguentado com algum vigor, pode melhorar quando encontrar condições um pouco mais favoráveis.

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As últimas discussions de hoje

15Z

TROPICAL STORM FRED DISCUSSION NUMBER 27
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015
1100 AM AST SAT SEP 05 2015

Fred has been decapitated again by strong westerly wind shear.
However, the low-level circulation continues to be vigorous. The
initial intensity remains at 35 kt, based on satellite estimates and
continuity. I will not speculate any more about the convection
redeveloping or not. The NHC forecast calls for little change in
intensity during the next 36 hours. If resilient Fred survives the
next day or so, there is a chance of slight re-intensification as
indicated by the SHIPS/GFS and SHIPS/ECMWF intensity guidance.

Fred is about to reach a break in the subtropical ridge where the
steering currents are weaker, and is now moving toward the west-
northwest at about 7 kt. A turn to the northwest and north should
begin later today, and by Sunday night, Fred should recurve as it
becomes embedded within the mid-latitude westerly flow. The NHC
forecast follows the trend of all the models, but is closer to the
GFS and the ECMWF solutions.

21z

TROPICAL DEPRESSION FRED DISCUSSION NUMBER 28
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015
500 PM AST SAT SEP 05 2015

Data from an ASCAT this morning confirmed what was estimated with
conventional visible images. Although Fred still has a very well
defined closed circulation, maximum winds have decreased to 30 kt.
In addition, the NASA Global Hawk has been been sending live
photographs of the tight circulation of low clouds associated with
Fred from 60 thousand feet. Fred has been devoid of deep convection
for a few hours, but as it occurred yesterday, new small convective
cells are currently trying to pop. As stated in the previous
forecast, if resilient Fred survives the strong shear during the
next 24 hours or so, there is a chance of slight re-intensification
after recurvature. This is indicated by the SHIPS/GFS and
SHIPS/ECMWF intensity guidance, and the GFS global model.

Fred is about to reach a break in the subtropical ridge where the
steering currents are weaker, and the cyclone appears to be moving
toward the northwest at about 5 kt. A turn to the north around the
ridge should begin tonight or early Sunday. Fred should then
recurve as it becomes embedded within the mid-latitude westerly
flow on Monday. The NHC forecast follows the guidance envelope, and
is close to the multi-model consensus with more weight given to the
GFS and the ECMWF global models.
 

TiagoLC

Super Célula
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Carnaxide, Oeiras
O Fred passou boa parte do dia "despido" de convecção, péssimo sinal, mas a circulação tem-se aguentado com algum vigor, pode melhorar quando encontrar condições um pouco mais favoráveis.

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As últimas discussions de hoje

15Z



21z
O teu "péssimo sinal" quer dizer que a tempestade enfraqueceu ou que fortaleceu?
 

Vince

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O teu "péssimo sinal" quer dizer que a tempestade enfraqueceu ou que fortaleceu?

Mau sinal para o ciclone, sem convecção no centro ou pelo menos muito próxima ao centro a baixa em superfície começa lentamente a "encher" e a circulação a diminuir de ritmo, pois não há mecanismo que a mantenha. De qualquer forma estava mais ou menos previsto para já esta degradação.
 

lserpa

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Horta, Matriz, (90m)
[nQUOTE="Orion, post: 506169, member: 3817"]/
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/QUOTE]
Independentemente que ele chegue aqui, ou não, vamos ser claramente influenciados indiretamente.. Se emergir como a depressão que passará por cá, vai haver muita energia... Digamos que será um sistema híbrido..., metade tropical e outra extra tropical....
 
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