Furacão HELENE (Atlântico 2024 #AL09)

  • Thread starter Thread starter Afgdr
  • Data de início Data de início
SUMMARY OF 900 PM EDT...0100 UTC...INFORMATION
----------------------------------------------
LOCATION...29.1N 84.2W
ABOUT 65 MI...105 KM W OF CEDAR KEY FLORIDA
ABOUT 90 MI...145 KM S OF TALLAHASSEE FLORIDA
MAXIMUM SUSTAINED WINDS...140 MPH...225 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 24 MPH...39 KM/H
MINIMUM CENTRAL PRESSURE...941 MB...27.79 INCHES

$$
Forecaster Bucci/Sardi

As rajadas podem atingir as 155 mph ≈ 249 km/h... Catastrófico! :(


O seu aspeto nas imagens de satélite é impressionante...


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É possível que a estação em Perry não consiga registar o verdadeiro valor da velocidade do vento, as 76 mph já aparecem de resto mais a norte até.
Note-se que o vento máximo sustentado depende muito do quadrante em que se situa a estação relativamente à direcção do movimento do olho.
Aqui será talvez no quadrante nordeste ou mesmo Leste, e tem sido realmente nesse quadrante que têm sido registados os maiores valores, em estações que deixaram de transmitir. Perry não está nesse quadrante, está a norte.

Entretanto, o Aviso 15 insistia nos 120 nós de vento máximo sustentado.
Hurricane Helene Discussion Number 15
NWS National Hurricane Center Miami FL AL092024
1100 PM EDT Thu Sep 26 2024

The hurricane is about to make landfall in the Florida Big Bend
region. Timely observations from Air Force and NOAA Hurricane
Hunter aircraft showed that Helene continued to strengthen rapidly
to Category 4 status before it approached the coast, with the
central pressure falling at about 3 mb per hour since this
afternoon. Peak 700 mb flight-level winds from the aircraft were
136 kt, corresponding to an intensity of about 120 kt, which might
be a bit conservative. Radar and satellite images show numerous
mesocyclones rotating around the eyewall.

The large hurricane continues moving rapidly north-northeastward
with the latest initial motion estimated to be 015/21 kt. A
generally northward track is expected overnight, taking the center
from southern to northern Georgia through early Friday morning.
Later on Friday and Saturday, Helene should slow down considerably
while it interacts with a mid-level low to its northwest and west.
The weakening system is likely to become nearly stationary in 48-60
hours. The official track forecast follows the dynamical model
consensus.

Although the system will weaken as it moves over land, the fast
forward speed of Helene during the next 12 hours or so will result
in a far inland penetration of strong winds over parts of the
southeastern United States, particularly over Georgia, including
strong gusts over the higher terrain of the southern Appalachians.
Accordingly, a higher-than-normal gust factor is indicated in the
official forecast while Helene is inland.

KEY MESSAGES:

1. A catastrophic and deadly storm surge is occurring along portions
of the Florida Big Bend coast, where inundation could reach as high
as 20 feet above ground level, along with destructive waves. There
is also a danger of life-threatening storm surge along the remainder
of the west coast of the Florida Peninsula.

2. Catastrophic hurricane-force winds are occurring near the coast
within the eyewall of Helene and will spread inland over portions
of northern Florida and southern Georgia.

3. Damaging wind gusts will penetrate well inland over portions of
Georgia and the Carolinas tonight, particularly over the higher
terrain of the southern Appalachians. Residents in these areas
should be prepared for the possibility of long-duration power
outages. If you use a generator after the storm, be sure it is
placed outside at least 20 feet away from doors, windows, and
garages to avoid deadly carbon monoxide poisoning.

4. Catastrophic and life-threatening flash and urban flooding,
including numerous significant landslides, is expected across
portions of the southern Appalachians through Friday. Considerable
to locally catastrophic flash and urban flooding is likely for
northwestern and northern Florida and the Southeast through Friday.
Widespread significant river flooding and isolated major river
flooding are likely.


FORECAST POSITIONS AND MAX WINDS

INIT 27/0300Z 29.9N 83.9W 120 KT 140 MPH
12H 27/1200Z 33.9N 84.0W 55 KT 65 MPH...INLAND
24H 28/0000Z 36.9N 86.2W 30 KT 35 MPH...POST-TROP/EXTRATROP
36H 28/1200Z 36.8N 87.5W 25 KT 30 MPH...POST-TROP/EXTRATROP
48H 29/0000Z 36.9N 86.9W 20 KT 25 MPH...POST-TROP/EXTRATROP
60H 29/1200Z 37.1N 86.4W 20 KT 25 MPH...POST-TROP/EXTRATROP
72H 30/0000Z...DISSIPATED

$$
Forecaster Pasch
 
Não falhei por muito, apenas 6 minutos:

"
000
WTNT64 KNHC 270319
TCUAT4

Hurricane Helene Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL092024
1120 PM EDT Thu Sep 26 2024

...HELENE MAKES LANDFALL IN THE FLORIDA BIG BEND...

Based on NWS Doppler radar data, the eye of Helene has made landfall
as a Category 4 hurricane in the Florida Big Bend region at about
11:10 PM EDT (0310 UTC) just east of the mouth of the Aucilla
River. This is about 10 miles (15 km) west-southwest of Perry,
Florida. Based on data from Air Force reconnaissance aircraft, the
maximum sustained winds are estimated to be 140 mph (225 km/h) and
the minimum central pressure is 938 mb (27.70 inches).


SUMMARY OF 1110 PM EDT...0310 UTC...INFORMATION
----------------------------------------------
LOCATION...30.0N 83.7W
ABOUT 70 MI...115 KM NNW OF CEDAR KEY FLORIDA
ABOUT 45 MI...70 KM ESE OF TALLAHASSEE FLORIDA
MAXIMUM SUSTAINED WINDS...140 MPH...225 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 24 MPH...39 KM/H
MINIMUM CENTRAL PRESSURE...938 MB...27.70 INCHES

$$
Forecaster Bucci/Sardi/Brown/Pasch/Hagen"
 
Helene manteve a sua intensidade antes do landfall - ventos máximos sustentados de 140 mph ≈ 225 km/h (cat 4) e rajadas até 155 mph ≈ 249 km/h. A pressão mínima no seu núcleo é de 938 hPa.

Movimenta-se para NNE a 24 km/h ≈ 39 km/h. Se a velocidade fosse menor, os danos seriam mais catastróficos ainda...

O momento do landfall:

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Continuar-se-ão a registar condições de furacão em partes dos estados da Flórida, Geórgia e Alabama e condições de tempestade tropical em partes dos estados da Flórida, Geórgia, Alabama, Carolina do Norte e Carolina do Sul.

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Movimenta-se para NNE a 24 km/h ≈ 39 km/h. Se a velocidade fosse menor, os danos seriam mais catastróficos ainda...
Sem dúvida, e a velocidade deste é invulgar para um Cat.4.

Esta estação está em posição de apanhar o pior durante mais tempo, está na parede Leste do olho, assim como esta.

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