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Hurricane Hector Discussion Number  17
NWS National Hurricane Center Miami FL       EP102018
200 PM PDT Sat Aug 04 2018

Satellite images indicate that the small eye of Hector has grown
larger over the past several hours, with a rapid axisymmetrization
of the eyewall convection.  It seems that the eyewall cycle has
completed itself rather quickly, with one distinct eyewall now
noted.  Dvorak estimates are on the rise again, and the latest
initial wind speed is set to 110 kt, which is a blend of the latest
satellite estimates. While there has been no scatterometer data
during the past day or so, the microwave data show that Hector has
grown in size, so the initial wind radii have been expanded,
although are smaller than the latest CIMSS and CSU/CIRA estimates.

Hector appears to be in the process of becoming an annular
hurricane, with little outer banding and a fairly symmetric inner
core.  This subset of hurricanes is known to occur under moderate
SSTs below 28.5C, with light easterly shear and no trough
interactions.  The bottom line for the intensity forecast is that
these conditions are likely to persist near Hector for the next few
days, and intensity guidance is known to have a low bias for annular
hurricanes.  The new intensity forecast is raised from the previous
one, and is near or above the guidance, showing only a slow demise
over the central Pacific as environmental conditions gradually
deteriorate.

Hector continues a westward motion of 270/10 kt. A large subtropical
ridge to the north should steer the hurricane generally westward
throughout the forecast period, with Hector gradually gaining some
latitude on Sunday and beyond due to a weakness in the ridge.  By 96
hours, most of the guidance shows a more due-westward motion south
of the Hawaiian Islands.  The only significant change from the past
advisory is a slightly slower forward speed for the first couple of
days.

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
range.  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  04/2100Z 14.2N 133.7W  110 KT 125 MPH
 12H  05/0600Z 14.3N 135.2W  115 KT 130 MPH
 24H  05/1800Z 14.5N 137.4W  115 KT 130 MPH
 36H  06/0600Z 14.8N 139.9W  115 KT 130 MPH
 48H  06/1800Z 15.3N 142.7W  110 KT 125 MPH
 72H  07/1800Z 16.3N 148.7W  100 KT 115 MPH
 96H  08/1800Z 16.7N 154.5W   90 KT 105 MPH
120H  09/1800Z 17.0N 160.0W   85 KT 100 MPH

$$
Forecaster Blake

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