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Hurricane Hector Discussion Number  36
NWS Central Pacific Hurricane Center Honolulu HI   EP102018
1100 PM HST Wed Aug 08 2018
 
Based on reflectivity data from the South Point WSR-88D radar om the
Big Island, microwave images, and satellite data, it appeared that
Hector went through an eyewall replacement cycle late this
afternoon. Since this reorganization of the hurricane appears to
be complete now, the eye of Hector has warmed and become much better
defined in infrared satellite imagery during the past few hours. As
a result, the satellite fix agencies provided subjective Dvorak
satellite-based intensity estimates ranging from 102 kt to 115 kt.
The latest ADT estimate from UW-CIMSS is near 105 kt. Based on a
blend of all of this input, we are maintaining the initial intensity
for this advisory at 100 kt. Hector has been traveling nearly due
west this evening, so the latest motion is 270/14 kt. Note that
Hector passed about 25 n mi south of buoy 51004 earlier this
evening. Wind gusts of 66 kt and seas up to 30 feet were observed at
this buoy around 0700z this evening.
 
Hector is expected to continue moving westward along the southern
periphery of a strong mid-level ridge located north of the main
Hawaiian Islands. This ridge is forecast to move little through
Thursday. Hector is expected to gradually turn toward the
west-northwest in 36-48 hours as it reaches the southwestern
periphery of the ridge. After that, a more pronounced turn toward
the northwest is anticipated after 72 hours. The updated track
forecast lies close to the previous forecast and a tightly-packed
guidance envelope through day 3. Increased guidance spread on days 4
and 5 arises due to differences in the forecast strength and
position of the ridge, and a developing low aloft to the northwest
of Hector. The latest forecast adjusts the track slightly to the
right of the previous forecast. This is based on the latest
consensus guidance, including the TVCN and GFEX, as well as the
HWRF.

Since Hector appears to be maintaining its intensity after the
eyewall replacement cycle, we have opted to keep its intensity
steady through 48 hours. After that, some gradual weakening is
possible from days 3 through 5 as it starts to encounter cooler
water temperatures and increasing southwesterly shear. Interests on
Johnston Island should monitor the progress of Hector. Based on the
latest wind speed probabilities, a Tropical Storm Watch may be
required for Johnston Island on Thursday.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/0900Z 16.6N 158.5W  100 KT 115 MPH
 12H  09/1800Z 16.7N 160.7W  100 KT 115 MPH
 24H  10/0600Z 17.0N 163.4W  100 KT 115 MPH
 36H  10/1800Z 17.5N 166.1W  100 KT 115 MPH
 48H  11/0600Z 18.4N 168.7W  100 KT 115 MPH
 72H  12/0600Z 20.6N 173.0W   95 KT 110 MPH
 96H  13/0600Z 24.0N 178.0W   85 KT 100 MPH
120H  14/0600Z 27.5N 177.5E   70 KT  80 MPH
 
$$
Forecaster Houston
 
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