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Hurricane Fernanda Discussion Number  27
NWS National Hurricane Center Miami FL       EP062017
800 AM PDT Tue Jul 18 2017

Fernanda's eye is only intermittently visible in the shortwave
infrared imagery this morning.  The deep convection is still quite
cold and symmetric around the center and a 1016Z AMSR2 microwave
image showed that a nearly complete eyewall was present.  Subjective
Dvorak classifications from SAB and TAFB and the objective ADT have
dropped slightly, so an initial intensity of 85 kt is analyzed.

The hurricane is moving toward the northwest at 8 kt.  Fernanda's
motion is being influenced by a deep-layer subtropical ridge to its
northeast and a mid-level trough to its northwest.  In a couple
of days, the trough lifts out and a mid-level ridge builds in north
of Fernanda causing the tropical cyclone to turn back toward the
west-northwest or west.  The official track forecast is based upon
the tightly clustered TVCN multi-model track consensus and is
nearly identical to the previous advisory.

Fernanda should continue to steadily weaken during the next couple
of days as it ingests stable, dry air over increasingly cooler
SSTs.  In two to three days, southwesterly vertical shear should
substantially increase and further contribute to Fernanda's
weakening.  The official intensity forecast - nearly the same as
from the previous advisory - is based upon a blend of the LGEM/SHIPS
statistical guidance and the COAMPS mesoscale hurricane model.

No scatterometer or AMSU size measurements have been available
recently, so the initial and forecast wind radii have been
maintained.

FORECAST POSITIONS AND MAX WINDS

INIT  18/1500Z 15.6N 133.3W   85 KT 100 MPH
 12H  19/0000Z 16.3N 134.1W   75 KT  85 MPH
 24H  19/1200Z 17.0N 135.2W   65 KT  75 MPH
 36H  20/0000Z 17.5N 136.7W   55 KT  65 MPH
 48H  20/1200Z 18.0N 138.3W   50 KT  60 MPH
 72H  21/1200Z 18.8N 141.6W   40 KT  45 MPH
 96H  22/1200Z 19.5N 145.0W   35 KT  40 MPH...POST-TROPICAL
120H  23/1200Z 20.0N 149.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Landsea

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