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Hurricane Kenneth Discussion Number  11
NWS National Hurricane Center Miami FL       EP132017
800 PM PDT Sun Aug 20 2017

Kenneth has rapidly intensified into a major hurricane this
evening, as the eye has dramatically warmed and the surrounding
cloud tops of the eyewall have cooled.  At 00Z, a blend of TAFB,
SAB, and ADT Dvorak classifications averaged maximum winds of
95 kt. However, the continued convective development in the last
three hours suggests that the advisory intensity be boosted to
100 kt, and even that may be conservative.

While the hurricane has shown an impressive evolution in the last
day, this should not continue much longer.  Kenneth will reach the
26C SST isotherm with drier, less unstable air late Monday, and it
is anticipated that Kenneth will peak by then.  In about three
days, the vertical shear will go up appreciably due to Kenneth
approaching an upper-level trough.  The combination of the hostile
thermodynamics and shear should cause a steady weakening through
the forecast period.  Kenneth's deep convection is likely to
dissipate in three to four days, signaling the system's
transformation to a post-tropical cyclone.  The official intensity
forecast is substantially higher than previously in the short-term
due to the unanticipated rapid intensification, but similar for 36
hours and beyond.  This prediction is closest to a blend of the HMON
dynamical model and the LGEM/SHIPS statistical models.

The hurricane is moving toward the west-northwest at 9 kt, steered
by a weak mid-level ridge to its northeast.  Kenneth should
gradually turn toward the north-northwest during the next couple of
days at about the same rate of forward speed, as it rounds the
mid-level ridge and is impacted by a cut-off mid- to upper-level low
farther north.  Once Kenneth becomes a post-tropical cyclone in
about 4 days, its forward speed should slow as it reaches a weaker
steering flow.  The official track forecast is nearly unchanged
through day 2 and is farther north beyond that time, based upon the
HFIP Corrected Consensus Approach.


FORECAST POSITIONS AND MAX WINDS

INIT  21/0300Z 16.8N 129.1W  100 KT 115 MPH
 12H  21/1200Z 17.4N 130.4W  110 KT 125 MPH
 24H  22/0000Z 18.7N 131.7W  100 KT 115 MPH
 36H  22/1200Z 20.3N 132.7W   85 KT 100 MPH
 48H  23/0000Z 22.1N 133.6W   70 KT  80 MPH
 72H  24/0000Z 25.5N 135.0W   50 KT  60 MPH
 96H  25/0000Z 28.5N 136.0W   40 KT  45 MPH...POST-TROPICAL
120H  26/0000Z 30.0N 136.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Landsea

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