Tropical Storm Ophelia Discussion Number   8
NWS National Hurricane Center Miami FL       AL172017
1100 PM AST Tue Oct 10 2017

Ophelia has lost some of its outer banding this evening, but a
well-defined band of convection remains over the southeastern and
southern portion of the circulation. A 2322 UTC ASCAT overpass
again suggests that the winds are not as strong what is indicated by
the Dvorak satellite estimates.  The highest winds in the ASCAT pass
were 35 kt, but with some undersampling consideration the initial
intensity is set to 45 kt.

Ophelia is moving southeastward or 140/5 kt. The cyclone should
continue to move southeastward or east-southeastward during the
next 24 hours while it remains embedded within a mid- to
upper-level trough.  After that time, Ophelia is forecast to turn
eastward, then northeastward and begin to accelerate by day 3 ahead
of a deepening mid-latitude trough over the north-central Atlantic.
The latest run of the GFS shifted eastward and is very similar to
the 12Z ECMWF, and the previous NHC track forecast.  These
typically reliable models are along the southern edge of the track
envelope, and the NHC forecast remains there as well.

The cyclone is expected to be within a low shear environment and
over marginally warm sea surface temperatures during the next 2 to 3
days.  These conditions favor strengthening and the NHC forecast
again calls for Ophelia to become a hurricane in about 36 hours,
although the forecast wind speed through 24 hours is slightly less
than the previous advisory due to the lower initial intensity.
Later in the period, baroclinic dynamics are expected to keep
Ophelia a strong cyclone over the northeastern Atlantic through day
5 when the system is forecast to become fully extratropical.


FORECAST POSITIONS AND MAX WINDS

INIT  11/0300Z 30.7N  37.6W   45 KT  50 MPH
 12H  11/1200Z 30.3N  37.0W   50 KT  60 MPH
 24H  12/0000Z 30.1N  36.5W   55 KT  65 MPH
 36H  12/1200Z 30.2N  36.0W   65 KT  75 MPH
 48H  13/0000Z 30.7N  35.0W   70 KT  80 MPH
 72H  14/0000Z 32.5N  30.8W   70 KT  80 MPH
 96H  15/0000Z 35.7N  23.2W   70 KT  80 MPH
120H  16/0000Z 41.0N  14.0W   65 KT  75 MPH...POST-TROP/EXTRATROP

$$
Forecaster Brown

dana‏ @Carretero45  13 minHace 13 minutos
Evolución de Ophelia según ECMWF: transición extratropical con ciclogénesis explosiva incluida. El viento será mayor que en su fase tropical

Gorka Hermoso‏ @GorkaHermoso1  18 minHace 18 minutos
Como estaba previsto, la salida determinista de ayer se acopla a la probabilista. Lo más probable es que #Ophelia no toque ni a Galicia.

Juan J. González‏ @glezjuanje  4 hhace 4 horas
Tanto GFS como IFS están modelizando una transición tipo seclusión  cálida, parecida a H. Sandy. Especialmente peligrosa e incierta.

Juan J. González‏
@glezjuanje
El CPS es claro; la transición no es la típica "cold-core" si no una del típo seclusión cálida mientras el ciclón transiciona (anómala).