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Hurricane Hector Discussion Number  21
NWS National Hurricane Center Miami FL       EP102018
200 PM PDT Sun Aug 05 2018

Hector continues to exhibit an impressive satellite presentation. A
1559 UTC SSMIS microwave overpass suggests that Hector likely
completed an eyewall replacement since this morning, with the eye
becoming better defined.  Both conventional satellite imagery and
the aforementioned microwave data show little in the way of banding
outside of the symmetric CDO, suggesting that Hector has some
characteristics of an annular hurricane.  Subjective satellite
intensity estimates are T6.0/115 kt from TAFB and SAB, and the
latest UW/CIMSS objective estimates are up to T6.1 or 117 kt. As
result, the initial wind speed is increased to 115 kt, making Hector
a category 4 hurricane once again.

Hector is forecast to remain within very low vertical wind shear
while it traverses SSTs of around 27C during much of the forecast
period.  However, the hurricane will be moving into an area of
drier mid-level air which is likely to induce some weakening later
in the forecast period.  Given Hector's annular-like structure,
the NHC intensity forecast shows a more gradual rate of weakening
since annular hurricanes tend to be more stable and weaken more
slowly.  The NHC intensity forecast is in best agreement with the
HFIP corrected consensus model, HCCA.

The hurricane continues moving westward or 275/11 kt. There is
been no change to the track forecast reasoning.  Hector is forecast
to move westward to west-northwestward during the next day or so to
the south of a deep-layer subtropical ridge.  The ridge is expected
to strengthen to the north of the Hawaiian Islands by mid-week
which is expected to turn the hurricane westward.  The models
continue to be in good agreement on this general scenario but some
cross-track spread remains.  The NHC forecast is once again near the
middle of the guidance envelope, close to the various consensus
models.

The NOAA G-IV aircraft will be releasing dropsondes as it
circumnavigates Hector during its flight to Hawaii to support
forecast operations over the next few days.  Data from these
dropsondes should be incorporated into this evening's 0000 UTC
dynamical models.

While the official forecast track continues to lie south of the
Hawaiian Islands, only a slight deviation to the north of the
forecast track would significantly increase potential impacts on
the Hawaiian Islands. It is a good time for everyone in the Hawaiian
Islands to ensure they have their hurricane plan in place.  For
additional information on any potential local impacts from Hector in
Hawaii, please refer to products issued by the NWS Weather Forecast
Office in Honolulu at: http://www.prh.noaa.gov/hnl


FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 14.4N 138.0W  115 KT 130 MPH
 12H  06/0600Z 14.7N 139.8W  110 KT 125 MPH
 24H  06/1800Z 15.3N 142.4W  105 KT 120 MPH
 36H  07/0600Z 15.9N 145.3W  100 KT 115 MPH
 48H  07/1800Z 16.4N 148.4W   95 KT 110 MPH
 72H  08/1800Z 16.7N 154.5W   90 KT 105 MPH
 96H  09/1800Z 17.0N 160.3W   85 KT 100 MPH
120H  10/1800Z 17.7N 166.0W   80 KT  90 MPH

$$
Forecaster Brown

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