Hurricane Hector Discussion Number 18
Wiki-Hurricanes Forecast Center
2:00 AM PDT Sun Aug 5 2018
Although the deepest convection is more symmetric around the eye of Hector compared to earlier, the extent of that convection has weakened somewhat. In addition, the eye has cooled slightly from around 11C to 6C. Both of these factors have caused UW-CIMSS ADT to decrease from T6.0/115kt to T5.5/102kt. This is in line with satellite estimates from SAB and TAFB as well. Given the sensitivity of Dvorak against the small stature of Hector, the initial intensity has only been slightly reduced to 110kt.
These fluctuations in strength are likely to continue for the next few days as Hector moves over marginal ocean temperatures within a low shear and just adequate moisture environment. A series of microwave passes from 20z to 03z showed that the prominent spiral band that existed earlier had dissipated, with a more distinct central dense overcast. This suggests Hector may be transitioning to an annular hurricane, which are more resilient than normal tropical cyclones. It also suggests Hector may not be prone to significant inner core changes in the immediate future. Most models are steady state for the next 36 hours, but the updated forecast continues to show the potential for some additional intensification before leveling off. On days three into four, cooler ocean temperatures, an exceptionally dry airmass, and potential influence from the Hawaiian Islands should cause some weakening. After continuing across the Central Pacific on day 5, redevelopment appears plausible.
Hector is moving west but should gain some latitude over the next day as the mid-level ridge to its north weakens slightly. By late Monday or Tuesday, a redevelopment of this high pressure should force Hector west, a trajectory that should keep the center south of the Hawaiian Islands, but still close enough to deliver tropical storm-force gusts.
FORECAST POSITIONS AND MAX WINDS
INIT 05/0900Z 110 KT 125 MPH
12H 05/1800Z 115 KT 130 MPH
24H 06/0600Z 120 KT 140 MPH
36H 06/1800Z 115 KT 130 MPH
48H 07/0600Z 105 KT 120 MPH
72H 08/0600Z 95 KT 110 MPH
96H 09/0600Z 85 KT 100 MPH ...CLOSEST APPROACH TO HAWAII
120H 10/0600Z 95 KT 110 MPH