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Hurricane Olivia Discussion Number  33
NWS National Hurricane Center Miami FL       EP172018
200 PM PDT Sat Sep 08 2018

The satellite presentation of Olivia has remained about the same
for the past several hours, as eyewall convection stays mostly
solid around the eye.  Dvorak estimates are basically unchanged, so
the initial wind speed is kept at 75 kt.  Olivia should stay a
hurricane for the next couple of days while it is experiencing light
shear, balanced by very dry air aloft and marginal but warming SSTs.
After the weekend, most of the guidance continue to indicate that
westerly shear should increase, and weakening is forecast while
Olivia approaches the Hawaiian Islands.  No significant changes
were made to the intensity forecast.

Olivia is moving westward at 13 kt.  There is no change to the
synoptic reasoning.  A building subtropical ridge should steer the
hurricane basically due westward for the next couple of days.
Thereafter, a mid-level ridge over Hawaii should cause Olivia to
lose some latitude and move west-southwestward toward the main
Hawaiian Islands.  The models are in better agreement on this cycle,
with the UKMET and GFS models trending more to the north, resulting
in a smaller guidance spread.  The official forecast is shifted a
bit northward to match the guidance trend.  A C-130 plane is
currently conducting a synoptic surveillance mission around Olivia,
which should hopefully aid later forecasts, which will be issued by
the Central Pacific Hurricane Center.


KEY MESSAGES:

1. Olivia is forecast to approach the main Hawaiian Islands from
the east on Tuesday, and pass close to or over the Islands on
Wednesday.  It is too soon to determine the exact location and
magnitude of any impacts, but interests in Hawaii should continue to
monitor the progress of Olivia, and use this time to enact your
hurricane action plan.

2.  Do not focus on the exact track or intensity forecast, or any
specific landfall location, as errors can be large at extended time
ranges.  Tropical storm or hurricane conditions could be felt
anywhere in the islands as significant impacts could extend well
away from the center.


FORECAST POSITIONS AND MAX WINDS

INIT  08/2100Z 21.7N 139.4W   75 KT  85 MPH
 12H  09/0600Z 21.9N 141.4W   70 KT  80 MPH
 24H  09/1800Z 22.0N 144.0W   65 KT  75 MPH
 36H  10/0600Z 22.0N 146.2W   65 KT  75 MPH
 48H  10/1800Z 22.0N 148.1W   65 KT  75 MPH
 72H  11/1800Z 21.4N 152.1W   55 KT  65 MPH
 96H  12/1800Z 20.4N 156.8W   50 KT  60 MPH
120H  13/1800Z 19.5N 162.0W   40 KT  45 MPH

$$
Forecaster Blake

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