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Hurricane Hector Discussion Number  20
NWS National Hurricane Center Miami FL       EP102018
800 AM PDT Sun Aug 05 2018

Hector continues to maintain a 10-15 n mi wide eye surrounded by a
ring of -60 to -70 degrees Celsius cloud tops.  The eye has become
slightly less distinct this morning and recent microwave data
suggest that an eyewall replacement cycle could be occurring.  A
1111 UTC AMSR2 microwave overpass shows a double eyewall structure
with the inner eyewall open to the southwest.  The various
subjective and objective satellite estimates are between 102-110
kt, and the initial wind speed is kept near the upper-end of these
estimates for now.

The hurricane is moving westward or 275/10 kt.  A westward to
west-northwestward motion is expected over the next day or so as
Hector is steered by a deep-layer ridge to its north.  The ridge is
forecast to strengthen north of the Hawaiian Islands by mid-week
which should cause the hurricane to move on a general westward
track throughout most of the remainder of the forecast period.
While all of the dynamical models are in agreement on the overall
scenario there is a fairly typical amount of cross-track spread with
the ECMWF along the southern edge of the guidance envelope and the
HMON and GFS along the northern side.  The updated NHC track
forecast is close to the latest consensus aids, and little overall
change to the previous forecast was required.

Hector is forecast to remain over warm SSTs and within a low shear
environment for the next couple of days, and it is possible for some
fluctuations in intensity to occur as the result of eyewall
replacements.  By 48 h, the hurricane is predicted to encounter some
drier mid-level air which is forecast to cause gradual weakening
after that time.  The latest NHC intensity forecast is a little
above the statistical guidance, closest to the HCCA and FSSE
intensity models.

While the official forecast track continues to lie south of the
Hawaiian Islands, it is too soon to determine what kind of impacts
might occur in the state, since track errors can be large at long
time ranges.  This remains 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  05/1500Z 14.4N 136.9W  110 KT 125 MPH
 12H  06/0000Z 14.6N 138.6W  105 KT 120 MPH
 24H  06/1200Z 15.1N 141.2W  105 KT 120 MPH
 36H  07/0000Z 15.7N 144.1W  100 KT 115 MPH
 48H  07/1200Z 16.3N 147.1W   95 KT 110 MPH
 72H  08/1200Z 16.8N 153.2W   90 KT 105 MPH
 96H  09/1200Z 17.2N 158.8W   90 KT 105 MPH
120H  10/1200Z 17.8N 164.2W   85 KT 100 MPH

$$
Forecaster Brown

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