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 WTPA45 PHFO 090859
 Hurricane Olivia Discussion Number  35
 NWS Central Pacific Hurricane Center Honolulu HI   EP172018
 1100 PM HST Sat Sep 08 2018
 Olivia remains poorly organized in infrared satellite imagery
 this evening. There have been hints of an eye in some of this
 imagery, but this feature is not persistent. The latest
 subjective Dvorak current intensity estimates were 4.0/65 kt from
 PHFO and SAB. Note that JTWC has only been doing fixes on this
 system since around 0000z, so their 3.5/55 kt was unrepresentative,
 since there is no valid MET available. The latest UW-CIMSS ADT
 estimate was 4.1/67 kt. We will maintain the current intensity at
 70 kt for this advisory.
 Olivia is now moving due west, so the initial motion estimate is
 270/14 kt. The hurricane is being steered to the south of a strong
 deep layer ridge situated north through west of the system.
 Little change in forward motion is expected during the next 2 days,
 since the ridging is forecast to build westward in tandem with
 Olivia. After 48 hours, the portion of the ridge to the west of
 Olivia is forecast to build, which will likely shunt the tropical
 cyclone on a more west-southwest motion. The track guidance remains
 fairly tightly clustered, and this forecast is very similar to the
 previous forecast track, which brings the center of Olivia across
 the main Hawaiian Islands between 72 and 96 hours. A more westward
 motion is expected to resume after Olivia's passage through the
 islands, as the upper ridge retreats westward and the circulation
 center becomes increasingly steered by the low-level trade wind
 Olivia is in a very weak vertical wind shear environment, but it is
 moving over marginal sea surface temperatures of 25.5C. The
 hurricane has likely traversed the coolest water it was going to
 encounter, but SSTs stay sub-27C until Olivia gets close to the
 islands. Note that the Ocean Heat Content (OHC) analysis from CIRA
 shows this parameter may increase starting around 36 or 48 hours, so
 this may help Olivia maintain its intensity longer than is currently
 forecast. However, vertical wind shear is expected to begin
 increasing after 48 hours, which will likely result in a gradual 
 weakening trend. Despite this trend, Olivia is forecast to remain a
 strong tropical storm during 72 to 96 hours, which could cause
 significant impacts in the main Hawaiian Islands. The latest
 intensity forecast closely follows the previous advisory.
 1.  It is important to recognize that errors in both forecast track
 and intensity, particularly at longer time ranges, can be large.
 While it is too soon to determine the location and magnitude of the
 worst impacts, all interests in Hawaii should continue to monitor
 the progress of Olivia, and use this time to prepare for the
 increasing likelihood of direct impacts from this system early next
 2.  Regardless of the exact track and intensity that Olivia takes
 as it approaches the islands, significant effects often do extend
 far from the center. In particular, the mountainous terrain of
 Hawaii can produce localized areas of strongly enhanced winds and
 rainfall, even well away from the tropical cyclone center.
 INIT  09/0900Z 21.8N 142.5W   70 KT  80 MPH
  12H  09/1800Z 21.8N 144.3W   70 KT  80 MPH
  24H  10/0600Z 21.8N 146.6W   70 KT  80 MPH
  36H  10/1800Z 21.8N 148.7W   70 KT  80 MPH
  48H  11/0600Z 21.7N 150.6W   65 KT  75 MPH
  72H  12/0600Z 20.9N 154.3W   55 KT  65 MPH
  96H  13/0600Z 19.8N 159.0W   50 KT  60 MPH
 120H  14/0600Z 19.6N 164.0W   40 KT  45 MPH
 Forecaster Houston
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