000
WTPZ43 KNHC 230835
TCDEP3

Tropical Storm Kenneth Discussion Number  20
NWS National Hurricane Center Miami FL       EP132017
200 AM PDT Wed Aug 23 2017

Conventional satellite imagery shows continued deterioration of
Kenneth's cloud pattern.  A moderate southwesterly wind shear regime
and oceanic temperatures of less than 24.5C have certainly taken its
toll on the cyclone.  A compromise of the subjective and objective
intensity estimates is the basis of lowering the initial intensity
to 50 kt for this advisory.  The aforementioned shear and cool
water, along with a continued intruding stable air mass from
the north, should result in a gradual spin down of Kenneth with
weakening to a remnant low in about 24 hours, and dissipation in 5
days.  The official intensity forecast follows the IVCN and
Decay-SHIPS models, and reflects the previous advisory's weakening
trend.

The initial motion is estimated to be north-northwestward, or
340/9 kt.  Kenneth should continue to move north-northwestward
during the next 36-48 hours in a break in a subtropical ridge
created by a high amplitude upper-level trough extending
northeastward from the eastern Hawaiian Islands.  Afterward, the
cyclone is forecast to degenerate to a vertically shallow remnant
low and move within the lower tropospheric southeasterly flow.
There is some increasing spread in the global models beyond day 3.
The UKMET and GFS indicate a more accelerated rate of weakening than
the ECMWF.  Consequently, the weaker Kenneth reflected in the
UKMET/GFS decreases significantly in forward speed and turns
west-northwestward in the shallow steering current while a more
vertically coherent cyclone in the ECMWF continues northwestward
with little reduction in speed. The NHC track forecast is a blend of
both of these solutions and is very close to the HFIP Corrected
Consensus model.

FORECAST POSITIONS AND MAX WINDS

INIT  23/0900Z 23.5N 134.3W   50 KT  60 MPH
 12H  23/1800Z 24.8N 135.0W   40 KT  45 MPH
 24H  24/0600Z 26.4N 135.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  24/1800Z 27.6N 136.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  25/0600Z 28.4N 136.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  26/0600Z 29.4N 137.3W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  27/0600Z 30.4N 138.9W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  28/0600Z...DISSIPATED

$$
Forecaster Roberts