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Hurricane Kenneth Discussion Number 15
NWS National Hurricane Center Miami FL EP132017
800 PM PDT Mon Aug 21 2017
Kenneth's previously distinct eye is clouding over as its eye
temperature cools, while the surrounding eyewall convection warms
and weakens. Correspondingly, the Dvorak classifications from TAFB,
SAB, and ADT have dropped and a blend of them suggests an intensity
of 95 kt at 00Z. Continued deterioration of the convective
structure is justification for maximum winds of 90 kt at advisory
time. While no recent size observations have been available,
earlier AMSU estimates along with the limited extent of the cold
cloud canopy suggest that Kenneth is a small tropical cyclone with
tropical-storm-force winds extending out about 80 nm from the
center on average.
Kenneth should continue to weaken - perhaps rapidly - under the
influence of cool to cold SSTs, dry and less unstable air, and
increasing southwesterly vertical shear. Kenneth should likely
lose all of its organized deep convection in 2-3 days, signaling
its transformation to a post-tropical cyclone at that time. The
official intensity forecast is based upon the tightly packed
dynamical and statistical model guidance and is a bit lower than the
previous advisory.
The hurricane is moving toward the northwest at about 9 kt, as it
rounds the southwestern periphery of a weak mid-level ridge and
toward a mid- to upper-level low farther north. Over the next
couple of days, Kenneth should turn toward the north-northwest at
about the same rate of speed. Once Kenneth becomes a post-tropical
cyclone, it should turn back toward the northwest and slow its
forward speed within the weak, low-level tradewinds. The official
track forecast is based upon the usually reliable global and
hurricane dynamical models, minus the substantially slower and to
the left UKMET solution (which has not been performing well thus far
this season). The new track forecast is slightly northeast of the
previous advisory.
FORECAST POSITIONS AND MAX WINDS
INIT 22/0300Z 19.2N 132.1W 90 KT 105 MPH
12H 22/1200Z 20.4N 132.9W 75 KT 85 MPH
24H 23/0000Z 22.2N 134.0W 60 KT 70 MPH
36H 23/1200Z 24.0N 134.9W 50 KT 60 MPH
48H 24/0000Z 25.6N 135.8W 40 KT 45 MPH
72H 25/0000Z 28.5N 136.4W 35 KT 40 MPH...POST-TROPICAL
96H 26/0000Z 30.5N 137.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 27/0000Z 31.5N 137.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
Forecaster Landsea
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