ZCZC HFOTCDCP1 ALL TTAA00 PHFO DDHHMM Tropical Storm Hector Discussion Number 52 NWS Central Pacific Hurricane Center Honolulu HI EP102018 1100 PM HST Sun Aug 12 2018 Hector's appearance has severely degraded according to satellite imagery this evening. The low-level circulation center (LLCC) is becoming almost entirely exposed, and the last area of deep convection has nearly dissipated, leaving behind mainly cirrus debris. This is not unexpected given the vertical wind shear of 11 to 14 kt from the south-southwest according to the latest SHIPS and UW-CIMSS analyses. The most recent subjective Dvorak intensity estimates are T3.5/55 knots from PHFO and SAB, and T3.0/45 knots from JTWC based on a shear pattern. The UW-CIMSS ADT estimate is T2.5/35 knots. Based on all of this guidance, we are lowering the initial intensity to 55 knots for this advisory. Since we can easily monitor the movement of the exposed LLCC in satellite imagery, the initial motion is set at 295/15 knots. The track forecast has been adjusted slightly from the previous one. Surprisingly, the latest model guidance remains tightly clustered through 72 hours, with the spread in the forecast tracks increasing on Days 4 and 5. Hector is expected to continue on a west-northwest track along the eastern periphery of a retrograding upper-level low located just west of the International Date Line near Longitude 173E. As this low aloft continues to move west, an upper level ridge is forecast to build north of the Hector. This will likely keep the tropical storm moving toward the west-northwest during the next 48 hours. A gradual turn toward the northwest is expected in around 72 hours, followed by a turn toward the north on days 4 and 5, as Hector rounds the western end of the ridge. The latest forecast track remains very close to the consensus guidance. Note that since the system is sheared, the forecast track is also close to the TABS through 48 hours. Based on the latest forecast track, Hector will likely cross the International Dateline into the Northwestern Pacific on Monday. The latest intensity forecast is very close to the previous forecast package. The forecast indicates additional weakening is expected during the next 12 hours. Based on the current appearance and the continuing southwesterly shear of 10 to 15 knots, it is likely this will occur. The forecast guidance continues to show the shear may relax within 18 to 24 hours, but the system will likely be weaker by this time and will be moving over cooler sea surface temperatures. The intensity guidance is in fairly good agreement through 36 hours, so confidence during this portion of the forecast is fairly good. Most of the intensity guidance levels off during the 36 through 48 hour time frame, while the SHIPS guidance and GFS indicate some unrealistic strengthening. The main weakening trend is on days 3 and 4. In addition, Hector is forecast to transition to an extratropical gale low in about 96 hours. Since the current track continues to shift more toward the west, the Tropical Storm Watch has been discontinued for Kure Atoll and Midway Atoll. Note that large breaking waves are still likely to persist along the Northwestern Hawaiian Islands from tonight into Monday due to the southeast swell generated by Hector. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 24.9N 178.8W 55 KT 65 MPH 12H 13/1800Z 25.9N 178.9E 50 KT 60 MPH 24H 14/0600Z 27.0N 175.9E 50 KT 60 MPH 36H 14/1800Z 28.0N 172.8E 50 KT 60 MPH 48H 15/0600Z 29.2N 169.8E 50 KT 60 MPH 72H 16/0600Z 32.0N 164.5E 45 KT 50 MPH 96H 17/0600Z 36.0N 162.5E 35 KT 40 MPH 120H 18/0600Z 42.0N 164.5E 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Houston NNNN