Hurricane Ophelia Discussion Number  12
NWS National Hurricane Center Miami FL       AL172017
1100 PM AST Wed Oct 11 2017

Satellite images indicate that Ophelia continues to get better
organized.  The small eye has become better defined with deeper
convection near the center than 6 hours ago.  Intensity estimates
have continued to rise, and the objective/subjective Dvorak values
range from 77 kt to 90 kt.  The initial intensity is increased to
75 kt, on the low end of the estimates since Ophelia is over
marginal water temperatures and might not be as strong as the
satellite suggests.  Further strengthening is possible given the
fairly low shear environment and marginally warm SSTs, assuming the
hurricane moves around enough to not upwell much cooler water.
Ophelia should keep hurricane-force winds before it transitions into
a strong extratropical low in 3-4 days.  The intensity forecast is
higher than the previous one, near the model consensus.  Almost all
of the guidance now show Ophelia as a powerful extratropical low
affecting Ireland, northern Ireland and Great Britain early next
week.

The hurricane is moving slowly toward the northeast, caught in an
area of light steering south of a flat trough in the mid-latitude
Atlantic.  This trough is forecast to amplify over the central
Atlantic late Thursday, which should steer Ophelia northeastward or
east-northeastward at an increasing forward speed for the next few
days.  Little change was made to the forecast track, leaning on the
ECMWF side of the consensus, which results in generally a faster
track than the previous prediction.

Although all of the guidance keep the center offshore of the
Azores, a tropical storm watch or warning could be needed for the
eastern Azores on Thursday because of the increasing wind radii in
the northwestern quadrant of the cyclone.


FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 30.0N  35.7W   75 KT  85 MPH
12H  12/1200Z 30.4N  35.3W   80 KT  90 MPH
24H  13/0000Z 30.9N  34.6W   80 KT  90 MPH
36H  13/1200Z 31.7N  32.9W   75 KT  85 MPH
48H  14/0000Z 32.8N  30.2W   75 KT  85 MPH
72H  15/0000Z 37.0N  22.0W   75 KT  85 MPH
96H  16/0000Z 46.0N  14.0W   70 KT  80 MPH...POST-TROP/EXTRATROP
120H  17/0000Z 56.5N   8.5W   55 KT  65 MPH...POST-TROP/EXTRATROP

$$
Forecaster Blake