ZCZC HFOTCDCP1 ALL TTAA00 PHFO DDHHMM Hurricane Hector Discussion Number 43 NWS Central Pacific Hurricane Center Honolulu HI EP102018 500 PM HST Fri Aug 10 2018 While still an impressive hurricane, the satellite presentation of Hector has degraded slightly with some warming of the cloud tops surrounding the eye. Dvorak current intensity numbers from HFO, SAB, and JTWC remain at 6.0/115 kt, and CIMSS ADT held at 122 kt. Since Dvorak final T numbers from HFO and CIMSS ADT dropped since six hours ago and the satellite presentation has degraded slightly, the initial intensity has been lowered to 115 kt. Hector maintained more of a westerly component to its motion than expected today and lost some forward speed. The initial motion is set at west-northwest (290 degrees) at 12 kt. A low to mid level ridge far to the north will steer Hector along a similar motion in the short term, and as the ridge is weakened slightly late tonight and Saturday, Hector will make a turn toward the northwest. This general motion toward the northwest will continue into Wednesday. The forecast track was nudged to the left through the next three days due to the slight delay in the turn toward the west-northwest today. The forecast track runs near the middle of the guidance envelope and is close to the TVCN through Monday. Thereafter, the forecast track lies on the right side of the guidance envelope, even after considerable adjustment to the left. Slow weakening is expected during the next several days. Nearby SSTs are holding around 28C, but Hector is beginning to encounter southwesterly winds aloft ahead of an upper level trough centered less than 800 miles to the northwest. As Hector advances toward the upper level trough during the next couple of days, southwesterly vertical wind shear should more than double from approximately 15 kt at this time to about 30 kt. This, along with slowly decreasing SSTs by Sunday, is expected to result in weakening of Hector. The forecast rate of weakening is similar to the statistical and dynamical models through the next 36 hours of increasing vertical wind shear. From Sunday onward, the model spread increases significantly as shear relaxes, and the forecast was held closer to IVCN and SHIPS near the middle of the guidance envelope. Given the close approach to the Northwestern Hawaiian Islands on Sunday and Monday, a Tropical Storm Watch has been issued from Lisianski Island to Pearl and Hermes Atoll. Interests on Midway and Kure Atolls should monitor the progress of Hector. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 18.3N 168.3W 115 KT 130 MPH 12H 11/1200Z 19.1N 169.9W 110 KT 125 MPH 24H 12/0000Z 20.7N 171.8W 100 KT 115 MPH 36H 12/1200Z 22.6N 173.8W 85 KT 100 MPH 48H 13/0000Z 24.5N 176.0W 75 KT 85 MPH 72H 14/0000Z 27.2N 178.4E 65 KT 75 MPH 96H 15/0000Z 29.5N 173.0E 60 KT 70 MPH 120H 16/0000Z 31.7N 168.0E 55 KT 65 MPH $$ Forecaster Wroe NNNN