000
WTPZ42 KNHC 072034
TCDEP2

Hurricane Aletta Discussion Number   8
NWS National Hurricane Center Miami FL       EP022018
300 PM MDT Thu Jun 07 2018

An eye has become apparent in visible geostationary satellite
imagery, although the central deep convection is not very symmetric
on enhanced infrared imagery.  Based on a blend of objective and
subjective Dvorak T-numbers, the current intensity is estimated to
be 65 kt, which makes Aletta the first eastern North Pacific
hurricane of 2018.  Since the system should continue to traverse a
warm ocean and experience weak vertical shear for the next day or
two, additional strengthening is forecast.  By Saturday some
increase in shear is likely, which should cause weakening to
commence.  The official intensity forecast is at the high end of
the numerical guidance.

Aletta has been moving somewhat north of the previous track
projections, and the initial motion is about 300/5 kt.  The main
factors controlling the steering of the hurricane are a mid-level
ridge to the northeast and a weakness in the ridge to the northwest
of Aletta, as well as the future intensity of the cyclone.  There is
significantly more spread in the track guidance model than is usual
for an east Pacific tropical cyclone.  The GFS and HWRF, which
depict a stronger system, have the northernmost tracks.  The ECMWF,
which does not show that strong of a cyclone in its forecast,
predicts the southernmost track.  The official forecast lies between
these options and is close to the corrected consensus guidance.
This is somewhat north of the previous NHC track.

FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 15.3N 110.0W   65 KT  75 MPH
 12H  08/0600Z 15.6N 110.5W   75 KT  85 MPH
 24H  08/1800Z 16.1N 111.5W   80 KT  90 MPH
 36H  09/0600Z 16.5N 112.3W   80 KT  90 MPH
 48H  09/1800Z 17.1N 113.0W   75 KT  85 MPH
 72H  10/1800Z 18.7N 114.6W   60 KT  70 MPH
 96H  11/1800Z 19.3N 116.7W   45 KT  50 MPH
120H  12/1800Z 19.5N 118.5W   30 KT  35 MPH

$$
Forecaster Pasch