Diagrama de fase del GFS para Joaquín... la extratropicalización no se daría ya hasta su disipación (es decir, llegaría al N de la Península aún con características tropicales tras pasar por las británicas...)



¿La razón? La desconozco. Las SST son muy frías y la cizalladura en altura debería destrozarlo bastante... pero no, resiste. Se me ocurre que pueda volverse un ciclón anular, pero me extrañaría mucho...

Un saludo!

Mantiene una organización más que decente, aunque el ojo no esté limpio de nubosidad. El anillo convectivo es más intenso y simétrico que esta mañana! :D1

Ya está de lleno embebido en los westerlies, pero al desplazarse de forma tan veloz, la cizalladura no le hace tanto daño A cambio, el aire frío en altura está haciendo que el mecanismo de formación de convección haya cambiado de gasolina a diésel...

Enviado desde mi GT-I9506 mediante Tapatalk

Joaquín, degradado a tormenta tropical y comenzando con la transición extratropical

000
WTNT41 KNHC 072033
TCDAT1

TROPICAL STORM JOAQUIN DISCUSSION NUMBER  41
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112015
500 PM AST WED OCT 07 2015

Joaquin has begun its transition into an extratropical cyclone.
The cyclone's cloud pattern has become rather asymmetric, with the
center partially exposed on the west side of weakening deep
convection.  In addition, cold air is wrapping into the western
periphery of the circulation, with a warm frontal band becoming
better defined well northeast of the center.  Earlier ASCAT data
still showed a large area of 55 to 60 kt winds, so the initial wind
speed is held at 60 kt.

The storm should gradually lose strength while it moves over
progressively colder waters north of the Gulf Stream.  Deep
convection should disappear tonight when the SSTs drop below 20C,
and Joaquin is expected to become post-tropical at that time. Global
models are in good agreement on the cyclone becoming a large
extratropical low on Thursday when frontal features are forecast to
form near the center. The official intensity forecast is basically
an update of the previous one, and remains in close agreement with
the GFS forecast.

Joaquin is speeding eastward at 32 kt, embedded in strong westerly
flow north of the subtropical ridge, which should keep the cyclone
moving to the east or east-northeast at a slower forward speed for
another day or two. Thereafter, the cyclone should slow down even
more and turn east-southeastward due to it coming under the
influence of a developing deep-layer trough over western Europe.
The guidance continues to migrate southward, and the official
forecast is moved in that direction, near a blend of the Florida
State Superensemble and the ECMWF models.

The track, intensity, and wind radii forecasts for 12 hours and
beyond are primarily based upon guidance provided by the Ocean
Prediction Center.


FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 41.5N  41.0W   60 KT  70 MPH
 12H  08/0600Z 42.0N  35.3W   50 KT  60 MPH...POST-TROPICAL
 24H  08/1800Z 42.7N  28.3W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  09/0600Z 43.6N  23.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  09/1800Z 43.8N  19.4W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  10/1800Z 43.0N  14.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  11/1800Z 41.5N  10.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
120H  12/1800Z...DISSIPATED

$$
Forecaster Blake

Bien... Joaquin ya no es ciclón tropical, así que a partir de ahora tendremos que referirnos a él como ex-Joaquin. Pero ojo, en el momento de este aviso, era ciclón post-tropical, todavía NO extratropical al carecer aún de sistemas frontales.

Actualmente la nubosidad va pasando al norte de las Azores, pero el centro del ciclón se ve más al sur.

000
WTNT41 KNHC 080235
TCDAT1

POST-TROPICAL CYCLONE JOAQUIN DISCUSSION NUMBER  42
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112015
1100 PM AST WED OCT 07 2015

Satellite imagery indicates that the system no longer resembles a
tropical cyclone, with a disorganized area of multi-layered
cloudiness sheared off well to the northeast of the ill-defined
low-level center.  However, model analyses and surface data
indicate that the cyclone is not yet embedded within a frontal
zone, and therefore is not extratropical at this time.  Nonetheless,
since the system lacks sufficient organized deep convection to
qualify as a tropical cyclone, Joaquin is being declared as a post-
tropical cyclone, and advisories are being terminated.  Cyclone
phase space analyses from Florida State University indicate that the
system will become extratropical in about 12 hours, and this is
also shown in the official forecast.  The current intensity is set
at 55 kt in agreement with a recent scatterometer overpass.  Global
models show a gradual spindown of the cyclone over the next several
days, and so does the official forecast.

Post-tropical Joaquin continues to move rapidly toward the east,
or 080/30 kt, while embedded in strong mid-latitude westerlies.
The steering current is forecast to gradually weaken as a mid-level
trough deepens near the Greenwich meridian, and the cyclone should
move at a progressively slower forward speed over the period.  In
2-3 days, the system is forecast to turn southeastward ahead of
the abovementioned trough.  There is fairly good agreement among
the global models on this scenario.

The track, intensity, and wind radii forecasts are primarily based
upon guidance provided by the NOAA Ocean Prediction Center.

FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 42.0N  37.0W   55 KT  65 MPH...POST-TROPICAL
 12H  08/1200Z 42.5N  32.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
 24H  09/0000Z 42.8N  26.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  09/1200Z 42.5N  22.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  10/0000Z 42.5N  19.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  11/0000Z 42.0N  14.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  12/0000Z 40.5N  11.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  13/0000Z 39.0N  10.5W   35 KT  40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch