455 
 WTPA41 PHFO 061526
 TCDCP1
  
 Hurricane Hector Discussion Number  25
 NWS Central Pacific Hurricane Center Honolulu HI   EP102018
 500 AM HST Mon Aug 06 2018
  
 The satellite presentation of Hurricane Hector has improved
 overnight, with a well defined 10 to 15 nautical mile wide eye
 surrounded by a large ring of -70 to -80 Celsius cloud tops. The
 latest subjective Dvorak current intensity estimates from SAB and
 JTWC came in at 6.5 (127 knots), while PHFO came in at 6.0 (115
 knots). The latest estimate using the Advanced Dvorak technique from
 UW-CIMSS yielded 6.8 (135 knots). Given that Hector's satellite
 presentation has improved since the previous advisory, we have
 elected to raise the initial intensity to 125 knots which correlates
 well with a blend of the available intensity estimates. Hector has
 continued to track westward at about the same speed as the previous
 advisory, so the initial motion remains 280/13 knots.
  
 The latest model guidance remains tightly clustered and brings
 Hector just north of due west over the next 36 to 48 hours due to a
 weakness in the subtropical ridge to the northeast of the Hawaiian
 Islands. Beyond 48 hours, the subtropical ridge is forecast to build
 to the north of the Hawaiian Island chain, and this should steer
 Hector due westward from 48 to 96 hours, before bending back to the
 west-northwest beyond 96 hours as a digging upper level trough
 between 170W and the International Date Line begins to erode the
 western portion of the subtropical ridge. The new official forecast
 track is very close to the model consensus and nearly identical to
 the previous official track forecast.
  
 Hector will remain in a favorable low shear environment through the
 forecast period, but there are some factors that should lead to
 gradual weakening over the next few days. The hurricane will be
 traveling over marginal sea surface temperatures around 27C through
 Wednesday, before the SSTs increase slightly to around 28C to the
 south of the Hawaiian Islands Wednesday night through Friday.
 Additionally and likely more importantly, very dry mid-level air
 will begin to surround the storm beginning later today or tonight,
 and this is expected to lead to a slow and gradual weakening of the
 system through Wednesday night. The intensity of Hector is then
 expected to level off Wednesday night through Friday as it
 encounters the higher SSTs, with some indication from the HWRF that
 re-intensification could occur. The intensity forecast has been
 adjusted slightly higher than the previous forecast due to both the
 statistical and dynamical models trending higher and coming into
 somewhat better agreement. Given the recent better performance of
 the dynamical guidance in comparison to the statistical guidance,
 more weight was placed on the dynamical models when preparing the
 intensity forecast for this advisory package as well.
 
 A couple reconnaissance missions are scheduled to be flown today
 between 18Z and 00Z, one by the Air Force Reserve 53rd Weather
 Reconnaissance Squadron which will provide additional important data
 to assist in future track and intensity forecasts. The other will be
 a NOAA G4 mission which will sample the environment around Hector,
 providing valuable data for ingestion into the models. 
  
 While the official forecast track continues to lie to the south of
 the Hawaiian islands, only a slight deviation to the north of the
 forecast track would significantly increase potential impacts to
 the state of Hawaii. Now is a good time for everyone in the
 Hawaiian Islands to ensure that they have their hurricane plan in
 place. For additional information on any potential impacts from
 Hector in Hawaii, please refer to products issued by the NWS Weather
 Forecast Office here in Honolulu at: http://www.prh.noaa.gov/hnl .
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  06/1500Z 15.0N 141.9W  125 KT 145 MPH
  12H  07/0000Z 15.4N 144.0W  120 KT 140 MPH
  24H  07/1200Z 15.9N 146.9W  115 KT 130 MPH
  36H  08/0000Z 16.2N 149.9W  110 KT 125 MPH
  48H  08/1200Z 16.5N 153.0W  105 KT 120 MPH
  72H  09/1200Z 16.6N 159.3W   95 KT 110 MPH
  96H  10/1200Z 17.0N 165.4W   90 KT 105 MPH
 120H  11/1200Z 17.7N 170.6W   90 KT 105 MPH
  
 $$
 Forecaster Jelsema