009 
WTPZ42 KNHC 072042
TCDEP2

Hurricane Olivia Discussion Number  29
NWS National Hurricane Center Miami FL       EP172018
200 PM PDT Fri Sep 07 2018

Olivia continues to slowly weaken.  Deep convection in the eyewall
has been gradually decreasing in intensity and coverage, but it
still completely surrounds the eye.  A blend of the latest
satellite intensity estimates supports lowering the initial wind
speed to 95 kt.  Olivia still has an annular appearance with the
cloud pattern consisting of an inner core with little to no outer
bands.

The hurricane is moving west-northwestward at 14 kt.  There
has been no change to the track forecast reasoning.  Olivia is
forecast to move west-northwestward for another day or so before
turning to the west, or even west-southwest, as ridging builds to
the north of the system.  The NHC track forecast remains near the
middle of the guidance envelope, and in best agreement with the
consensus aids.  Based on this forecast, Olivia is expected to cross
into the central Pacific basin by late Saturday and approach the
Hawaiian Islands in 4 to 5 days.

Although Olivia remains in low wind shear conditions, the cyclone
is over fairly cool 25-26 deg C waters.  These marginal SSTs and an
increasingly drier and more stable air mass should cause the slow
weakening trend to continue through the forecast period.  However,
as mentioned in previous discussions, annular hurricanes like
Olivia often weaken slower than normal in these conditions, so it
is possible Olivia won't weaken as fast as some of the guidance
suggests.

FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 20.5N 133.9W   95 KT 110 MPH
 12H  08/0600Z 21.1N 135.9W   85 KT 100 MPH
 24H  08/1800Z 21.6N 138.5W   75 KT  85 MPH
 36H  09/0600Z 21.8N 141.2W   70 KT  80 MPH
 48H  09/1800Z 22.0N 143.7W   70 KT  80 MPH
 72H  10/1800Z 22.0N 148.0W   65 KT  75 MPH
 96H  11/1800Z 21.6N 151.8W   60 KT  70 MPH
120H  12/1800Z 20.5N 156.0W   50 KT  60 MPH

$$
Forecaster Cangialosi