Huracán Larry (Categoría 3)

[Wyoming]

Vamos calentando motores que ya se acerca el pico climatológico de la temporada de huracanes en el atlántico.

Este sistema tenia mucho soporte por varios modelos desde hace más de una semana ya, incluso cuando todavía la onda tropical estaba en el medio de Africa. De hecho, la señal que daban los modelos de que este sistema se forme rápidamente y alcance la categoría de huracán mayor era demasiado alta.

Larry fue upgradeada a depresión tropical ayer y hoy a tormenta tropical. A mediodía desarrollo un eye-like feature (un proto ojo) que fue producto de una pequeña intrusión de aire seco en su centro. Sin embargo, Larry siguió creando convección muy fuerte, especialmente en el cuadrante oeste. Lo que en un momento fue una pequeña intrusión de aire seco que "creo" un hueco en el centro del sistema, se termino convirtiendo en un ojo (!).

De hoy temprano

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Para ese entonces, una pasada de ASCAT revelo vientos de 40kts y un centro en niveles bajos bastante potable (los puntos blancos son ambigüedades no resueltas)

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Como había dicho, este sistema desde antes que se formara ya se preveía que iba a ser un bicho formidable. Y es tan así que la primera discusión sobre Larry por parte del NHC le daba un pico de 95kts (110mph; 175 km/), es decir, casi un categoría 3. Al rato aumentaron su nuevo pico a 105kts (120mph; 195 km/h), un categoría 3 de cajón.
Lo bueno de este sistema es que, por el momento, no afectara tierra (pero Bermuda...). Los diferentes modelos lo mandan OTS (out to sea; a mar abierto) por lo que debería ser un espectáculo mirarlo sin que inflija daño (a la Teddy 2020).



Última discusión del NHC sobre Larry. En negrita lo más importante, como siempre.

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726
WTNT42 KNHC 012035
TCDAT2

Tropical Storm Larry Discussion Number 5
NWS National Hurricane Center Miami FL AL122021
800 PM CVT Wed Sep 01 2021

Afternoon satellite imagery indicates that Larry continues to
become better organized, with visible imagery hinting at eye
formation and a partial SSM/IS overpass suggesting that a 37 GHz
convective ring is present around the center.
Satellite intensity estimates are now 65 kt from SAB and 55 kt from TAFB, and the
initial intensity is increased to 60 kt, which is a 30 kt increase
since this time yesterday satisfying the 24-h definition of rapid
intensification.

The initial motion is now 275/19 kt. Larry is expected to move
around the south and southwest sides of a subtropical ridge during
the next five days, with a general westward motion for 24-36 h,
followed by a turn toward the west-northwest and, by 96-120 h, a
turn toward the northwest. The spread in the track guidance after
36 h has decreased a little in the latest model runs. However, the
guidance envelope has again shifted a little to the west. The new
forecast track will also be shifted a little westward, and it lies
on the southern edge of the various consensus models.

Conditions appear favorable for additional rapid intensification
during at the next 36-48 h, and the intensity forecast now calls for
Larry to become a hurricane in less than 12 h and become a major
hurricane in about 48 h. Given current trends, this part of the
intensity forecast could be conservative. There is lower confidence
in the intensity forecast after 48 h. Larry is expected to
encounter somewhat increased shear, and around the 72 h point it is
expected to encounter some dry air. After 96 h, moderate shear is
forecast to continue, but the cyclone is expected to move into a
more moist air mass and over increasing sea surface temperatures.
On top of these factors, there is the good chance that Larry will
have fluctuations in intensity after it becomes a major hurricane
due to eyewall replacement cycles. The intensity guidance basically
keeps a steady intensity from 60-120 h, and the official forecast
follows that trend. However, this part of the intensity forecast is
in the middle of the guidance, and it is possible Larry could be
stronger than forecast during this time.


FORECAST POSITIONS AND MAX WINDS

INIT 01/2100Z 12.5N 29.4W 60 KT 70 MPH
12H 02/0600Z 12.6N 31.8W 70 KT 80 MPH
24H 02/1800Z 13.0N 34.9W 85 KT 100 MPH
36H 03/0600Z 13.7N 38.0W 95 KT 110 MPH
48H 03/1800Z 14.6N 40.9W 100 KT 115 MPH
60H 04/0600Z 15.6N 43.5W 105 KT 120 MPH
72H 04/1800Z 16.9N 46.2W 105 KT 120 MPH
96H 05/1800Z 19.5N 50.5W 105 KT 120 MPH
120H 06/1800Z 22.5N 54.0W 105 KT 120 MPH

Varios modelos vienen subiendo la intensidad de Larry con cada actualización, llevandolo a la categoría 4. Posiblemente esto se vea reflejado en el próximo parte del NHC.

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Track per NHC

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Actualmente:
8:00 PM CVT Wed Sep 1
Location: 12.5°N 29.4°W
Moving: W at 22 mph
Min pressure: 991 mb
Max sustained: 70 mph (110 km/h)

[Wyoming]

Buenas. Actualizo.

Hoy Larry se convirtió en el quinto huracán de la temporada actual. Además, como comenté anoche, le siguen aumentando el pico máximo esperado.

...LARRY BECOMES A HURRICANE OVER THE EASTERN TROPICAL ATLANTIC...

Larry's cloud pattern has gradually become better organized, with
deep convection increasing in coverage and intensity near the
center and a banding-type eye trying to form. Upper-level outflow
is most prominent over the western and northern portions of the
circulation. A well-defined low-level eye was apparent on an
AMSR-2 image from a few hours ago. Dvorak final T- and Current
Intensity-numbers from both TAFB and SAB are 4.0/4.0, corresponding
to an intensity of 65 kt. Based on these estimates, Larry is
upgraded to a hurricane, the fifth of the 2021 Atlantic season.

The hurricane is moving just slightly north of west, or 280/17 kt.
There are no important changes to the track forecast scenario from
the previous advisory. Larry is likely to move along the southern
and southwestern periphery of a strong deep-layer subtropical high
pressure area over the east-central Atlantic during the next few
days. This should result in a gradual turn toward the
west-northwest during the next 48-72 hours. A turn toward the
northwest is likely in 4-5 days as the system approaches a weakness
in the ridge. The track models are fairly well clustered on this
future direction of motion with some differences in forward speed.
The official track forecast is quite similar to the previous one
and is also very close to the latest dynamical model consensus,
TVCA.

Larry is expected to remain in an environment conducive for
strengthening over the next few days, with marginally warm
SSTs, low vertical shear, and surrounded by broad-scale anticyclonic
upper-level flow. Therefore, strengthening is likely, and the
official forecast calls for Larry to become a major hurricane in 48
hours or so. Some fluctuations in intensity due to eyewall
replacements are possible around and after that time. Late in the
forecast period, slightly drier air in the environment could limit
further intensification. The official intensity forecast is close
to the latest NOAA corrected consensus, HCCA, guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0900Z 13.0N 32.3W 65 KT 75 MPH
12H 02/1800Z 13.4N 34.7W 75 KT 85 MPH
24H 03/0600Z 14.0N 37.9W 85 KT 100 MPH
36H 03/1800Z 14.8N 40.9W 95 KT 110 MPH
48H 04/0600Z 15.8N 43.6W 100 KT 115 MPH
60H 04/1800Z 16.9N 46.1W 105 KT 120 MPH
72H 05/0600Z 18.3N 48.3W 110 KT 125 MPH
96H 06/0600Z 20.9N 52.1W 115 KT 130 MPH (categoría 4)
120H 07/0600Z 23.8N 55.4W 110 KT 125 MPH

La trayectoria no cambio casi nada, por lo tanto no deberia afectar tierra de momento. Sin embargo, Bermuda debería vigilar de cerca el bicho ya que dependiendo de que tan fuerte sea la alta presión en niveles altos, puede empujar a Larry un poco más al oeste-noroeste (impactando la isla) o más al norte (sin impactar la isla).

Lo bueno de este mes y con las ondas tropicales que se desarrollan en lo profundo atlántico este es que la climatología hace que recurven casi 100% a mar abierto. Los sistemas que alcanzaron la categoría de huracán al este de 35°W, recurvaron al norte (un sistema "mas fuerte" no siente tanto el efecto de una alta presión, sucede a la inversa con los sistemas débiles).


Más adelante en el tiempo, los modelos están viendo algo muy interesante con este bicho, algo que no es tan común en el atlántico.
En algún momento de su recorrido, Larry atravesará aguas "marginalmente" cálidas (27°C-28°C), aire seco (como nota el NHC) y cortante del este... ingredientes casi ideales para que Larry transicione a un sistema anular (sin las bandas exteriores características de estos sistemas). De hecho, el HWRF lo ve "anularizandose" en 48hr, con un ojo enorme y algo inestable. Esto coindice con el pronostico de ser un huracán mayor a 48hr por parte del NHC. Dejo animación completa + simulación de satelite.
Notar que, desde un principio, este modelo está inicializando correctamente a Larry (985mb vs 987mb NHC).

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Estado actual

5:00 AM AST Thu Sep 2
Location: 13.0°N 32.3°W
Moving: W at 20 mph
Min pressure: 987 mb
Max sustained: 75 mph

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Edito
Ahora cuenta con 80mph (70kts;130 km/h) y 985mb.
Pico máximo actualizado a 120kt (140mph; 220 km/h)

[Santiago Linari]

Formó "hot torres" duales. Deberían ayudarlo a intensificarse.

[Wyoming]

Pareciera que atravesó un ciclo de reemplazo del ojo, pero es dificil de saberlo con exactitud debido a una "brecha" temporal entre las pasadas de las imagenes.


Mantiene intensidad, aunque su apariencia mejora minuto a minuto.

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[Santiago Linari]

Interesante, es muy débil para tener un ciclo de reemplazo.
También leí que su ojo tuvo mesovórtices.

[Santiago Linari]

Larry alcanzó el estatus de huracán mayor.
115 mph y 1965 hPa.

Se tardó bastante en intensificarse finalmente. Y aún así le cuesta tener topes fríos en la parte central. ¿Intrsuciones de aire seco?
Los 26°C de temperatura del mar son marginalmente favorables. Eso probablemente influya también.

[Wyoming]

Que interesante como ayer seguia atravesando un ciclo de reemplazo del ojo. Pense que solo se daba con sistemas con intensidad mayor a 95kt (cat 3). Bueno, la cosa es que ayer trabajo bien su estructura interna para hoy poder mostrar su ojo majestuosamente.

Ayer, cuando era un categoría 2 y atravesaba el EWRC.


Interesante lo que comenta Phil. Para ponerlo en contexto, el año pasado, a esta altura, solo habíamos tenido un major (Laura). Teddy no se formaría hasta el 12-sep,alcanzado el estatus de huracán mayor el 17-sep.




Ya ayer comenzaba a mostrar una estructura desprovista de bandas exteriores. Es decir, había comenzado el proceso de anularización, con un ojo enorme y medio "rasgado".

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No obstante, pareciera que no será 100% anular debido a que las aguas por las que pasara en los próximos días son más cálidas (>28°C; lo que lo habilitaría a tener un ojo más pequeño) y un aumento de cortante (un poco + de lo previsto). Hilo.


Hoy a la mañana lucia así

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Para hoy, el domingo y el martes hay programados aviones de reconocimiento para investigar el sistema. El domingo haría su acercamiento más cercano a las Antillas Menores.
Hoy es claramente un sistema anular.

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Larry actualmente cuenta con 110kt, 958mb. Pico elevado a 125kts.

...LARRY LARGER AND A LITTLE STRONGER... ...DANGEROUS SURF AND RIP CURRENTS EXPECTED TO DEVELOP ALONG MANY WESTERN ATLANTIC SHORES NEXT WEEK...

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Overnight and this morning, Larry appears to have gone through a
rather quick eyewall replacement cycle (ERC). The most recent 1000
UTC GMI microwave pass suggests that Larry now has a much larger eye
and surrounding eyewall, with less evidence of concentric bands as
noted yesterday. On geostationary satellite the larger eye is also
becoming apparent on visible and infrared channels, though some left
over inner eyewall debris remains. Consistent with the larger eye,
an ASCAT-B pass received at 1226 UTC indicated that the 34-, 50-,
and 64-kt wind radii have expanded with Larry this morning. While
the most recent SAB and TAFB subjective Dvorak intensity estimates
have remain at 90 kt and 100 kt respectively, the
objective estimates are higher, with an earlier UW-CIMSS SATCON
estimate up to 112 kt, though it has recently been adjusted lower.
With the eye beginning to clear out on the most recent satellite
images, I am favoring the higher objective estimates, bringing Larry
up to 110 kt for this advisory.

Larry's track has remained fairly steady toward the west-northwest,
but just a touch slower and more poleward with the latest estimated
motion at 300/13 kt. This west-northwest motion is expected to
continue for the next several days with only a very gradual poleward
bend as Larry remains positioned to the south of an expansive
mid-level ridge extending westward ahead of Larry's expected path.
As has been the case the last several days, the track guidance is in
excellent agreement over the next 36-48 hours with more spread
becoming apparent thereafter. As discussed yesterday, the increase
in spread in the latter portion of the forecast appears to be
related to how much mid-level ridging stays north of Larry. The
ECMWF and its ensembles maintain more ridging that results in a
slower and more westward track, while the GFS and its ensembles
place more ridging east of Larry that results in a faster more
eastward track. The UKMET favors a solution closer to the ECMWF
while the Canadian favors a solution closer to the GFS. For now, the
latest NHC track has elected to remain close to the HFIP corrected
consensus approach (HCCA) which slightly favors the ECMWF solution
over the GFS. This latest track forecast is quite similar to the
previous one, but just a touch slower. Based on this forecast, Larry
will continue moving across the central Atlantic in the coming days,
and be approaching the latitude of Bermuda by the end of the
forecast period.

Conditions continue to remain favorable for additional
intensification over the next few days, with vertical wind shear
remaining under 10 kts, sea-surface temperatures gradually
increasing, and mid-level relatively humidity staying fairly moist.
However, by 48 hours, Larry will be impinging on the eastern edge of
a large upper-level mid-oceanic trough, which could result in an
increase in westerly vertical wind shear over the hurricane.
However, the models handle Larry's interaction with this synoptic
feature differently. The GFS suggests this upper-level trough will
fracture to the west fairly quickly, keeping a more favorable
upper-level pattern over Larry, while the ECMWF has a stronger
trough that takes longer to give way to Larry's upper-level outflow,
providing more westerly shear over the hurricane. Additional eyewall
replacement cycles are also possible in the coming days, which could
result in additional intensity fluctuations that are challenging to
predict ahead of time. For now, the latest NHC intensity forecast
keeps Larry intensifying over the next 24-36 hours, with only a very
gradual decay thereafter due to the somewhat less favorable
dynamical environment. The latest intensity forecast remains on the
high end of the guidance, noting that there still remain higher
outliers making Larry stronger than the 125 kt peak intensity
(HAFS-B, COAMPS-TC). Regardless of the details, Larry is expected to
remain a large major hurricane through the forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 16.8N 45.8W 110 KT 125 MPH
12H 05/0000Z 17.7N 47.5W 115 KT 130 MPH
24H 05/1200Z 19.1N 49.6W 120 KT 140 MPH
36H 06/0000Z 20.3N 51.5W 125 KT 145 MPH
48H 06/1200Z 21.5N 53.2W 120 KT 140 MPH
60H 07/0000Z 22.6N 54.8W 120 KT 140 MPH
72H 07/1200Z 23.8N 56.4W 115 KT 130 MPH
96H 08/1200Z 27.0N 59.4W 110 KT 125 MPH
120H 09/1200Z 31.6N 62.0W 100 KT 115 MPH

[Wyoming]

Que manera de ver mesovórtices en ese ojo.
Jaw-dropping.

[Santiago Linari]

Su aspecto se había deteriorado algo en su cuadrante sudoeste. Pero ahora mejoró.



Bajó a 120 mph. Tal vez la cortante lo está molestando.

[Santiago Linari]