585 
 WTPZ42 KNHC 071433
 TCDEP2
 
 Hurricane Olivia Discussion Number  28
 NWS National Hurricane Center Miami FL       EP172018
 800 AM PDT Fri Sep 07 2018
 
 Although Olivia is still a major hurricane, the cloud tops have
 warmed some over the past several hours and the eye is not quite as
 distinct as it was overnight.  All of the satellite intensity
 estimates have decreased this cycle, and the initial intensity is
 lowered to 100 kt using that data.  Satellite data indicate that
 Olivia is an annular hurricane with a well organized inner core, but
 with a lack of outer banding features.
 
 The hurricane is moving west-northwestward at 14 kt.  The track
 forecast philosophy appears fairly straightforward.  Olivia is
 expected to move westward to west-northwestward during the next few
 days as it remains steered by a subtropical ridge to its north.  By
 the end of the forecast period, a turn to the west-southwest is
 expected as ridging builds to the northwest of the cyclone.
 The NHC track forecast remains near the middle of the guidance
 envelope, in best agreement with the consensus aids.  Based on
 this forecast, Olivia is expected to cross into the central Pacific
 basin by late Saturday.
 
 Olivia is over cool 25-26 deg C waters, and it will remain over
 these waters during the next several days.  These marginal SSTs
 combined with drier air should cause a slow weakening trend through
 the forecast period.  However, as mentioned in previous discussions,
 research has proven that annular hurricanes like Olivia weaken
 slower than normal in these types of conditions.  Therefore, the
 NHC intensity forecast shows a slower rate of weakening than the
 IVCN and HCCA models.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  07/1500Z 20.1N 132.5W  100 KT 115 MPH
  12H  08/0000Z 20.7N 134.5W   90 KT 105 MPH
  24H  08/1200Z 21.3N 137.0W   80 KT  90 MPH
  36H  09/0000Z 21.7N 139.7W   75 KT  85 MPH
  48H  09/1200Z 22.0N 142.3W   70 KT  80 MPH
  72H  10/1200Z 22.3N 146.9W   65 KT  75 MPH
  96H  11/1200Z 22.0N 150.5W   60 KT  70 MPH
 120H  12/1200Z 21.0N 155.0W   55 KT  65 MPH
 
 $$
 Forecaster Cangialosi