558 WTPZ45 KNHC 042044 TCDEP5 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