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Hurricane Hector Discussion Number 39
NWS Central Pacific Hurricane Center Honolulu HI EP102018
500 PM HST Thu Aug 09 2018
Cloud top temperatures surrounding the eye of Hector have cooled
and the overall symmetry in the satellite images has improved
since six hours ago. Subjective Dvorak intensity estimates were
5.5/102 kt from PHFO and JTWC, and 6.0/115 kt from SAB.
CIMSS ADT increased at bit to 5.9/112 kt at 0000 UTC. Based on a
blend of the objective and subjective estimates and the overall
improvement in appearance, the initial intensity has been increased
to 110 kt. Hector's movement has been 275/15 kt and this is the
initial motion for this forecast package.
Hector continues to move westward to the south of a mid-level ridge.
The ridge is forecast to weaken as a low pressure system cuts
off near the Dateline over the next couple of days. This should
result in a gradual turn toward the west-northwest tonight and
Friday, followed by a more northwestward track. The latest
objective aids are in good agreement with this scenario. The
forecast mostly follows the previous package though 48 hours, then
was shifted slightly north at 72 and 96 hours to follow a slight
northward shift in the dynamical consensus.
In the face of recent realities, the intensity forecast calls for
slight strengthening of Hector tonight, followed by steady
weakening after 24 hours. The increase in strength is in line with
HWRF, HMON, and CTC2 which have verified the best so far. These
models also show a faster weakening after 48 hours but the forecast
shows a more conservative weakening trend for now. The weakening
appears to be mainly in response to increasing vertical shear.
A Tropical Storm Watch remains in effect for Johnston Island. If the
expected turn toward the west-northwest does not occur, tropical
storm conditions are possible there starting late Friday. Elsewhere,
interests in the Northwestern Hawaiian Islands, including Midway and
Kure Atolls and the Papahanaumokuakea Marine National Monument west
of French Frigate Shoals should monitor the progress of Hector.
FORECAST POSITIONS AND MAX WINDS
INIT 10/0300Z 17.1N 162.8W 110 KT 125 MPH
12H 10/1200Z 17.5N 165.4W 115 KT 130 MPH
24H 11/0000Z 18.5N 168.0W 115 KT 130 MPH
36H 11/1200Z 19.7N 170.0W 105 KT 120 MPH
48H 12/0000Z 21.7N 172.2W 95 KT 110 MPH
72H 13/0000Z 25.4N 176.9W 75 KT 85 MPH
96H 14/0000Z 28.5N 178.0E 55 KT 65 MPH
120H 15/0000Z 32.0N 174.0E 45 KT 50 MPH