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Hurricane Fernanda Discussion Number  28
NWS National Hurricane Center Miami FL       EP062017
200 PM PDT Tue Jul 18 2017

Somewhat surprisingly, Fernanda has made a small comeback this
afternoon as its eye has become distinct in the visible satellite
imagery in the midst of a ragged ring of very cold cloud tops.
Subjective Dvorak classifications from SAB and TAFB and the
objective ADT have increased some, so an initial intensity of 90
kt is analyzed.

The hurricane is moving toward the northwest at 7 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 track guidance is tightly clustered for
the first couple of days but at the extended range the guidance
shows more spread, especially along the track.  The official track
forecast is based upon the TVCN multi-model track consensus and is
nearly identical to the previous advisory.

Fernanda is expected 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.  By days 4 and 5, the winds from Fernanda may be
augmented some by a strong pressure gradient setting up north of the
tropical cyclone.  The official intensity forecast - nearly the same
as from the previous advisory - is based upon the IVCN multi-model
intensity consensus.

Once again, 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  18/2100Z 16.0N 133.9W   90 KT 105 MPH
 12H  19/0600Z 16.7N 134.7W   80 KT  90 MPH
 24H  19/1800Z 17.3N 135.9W   70 KT  80 MPH
 36H  20/0600Z 17.9N 137.5W   60 KT  70 MPH
 48H  20/1800Z 18.3N 139.1W   50 KT  60 MPH
 72H  21/1800Z 19.0N 142.7W   40 KT  45 MPH
 96H  22/1800Z 20.0N 146.5W   35 KT  40 MPH...POST-TROPICAL
120H  23/1800Z 20.5N 150.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Landsea

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