Hurricane Hector Discussion Number 11
Wiki-Hurricanes Forecast Center
2:00 AM PDT Fri Aug 3 2018
Hector's wild ride continues this morning. The cloud pattern of the hurricane has become better organized this evening, with a symmetric and intense central dense overcast. Microwave passes from around 2z showed that the inner core of Hector was still open to the north thanks to the moderate northeasterly wind shear and dry air entrainment that has been plaguing it this afternoon. Nonetheless, the eye is trying to make a comeback on infrared imagery. The satellite intensity estimate of T4.5/77kt from SAB earlier is unchanged, while UW-CIMSS ADT has stopped its bleeding around T3.9/63kt. The latter value is obviously too low and has been discounted. Given the unchanged value from SAB and the fact that the hurricane has become better organized since earlier, the initial intensity is increased to 95kt.
Hector's improvement in organization suggests the wind shear may already be declining. With upper-level winds set to decrease below 5kt, ocean temperatures expected to remain around 27C, and the immediate environment around the hurricane likely to remain adequately moist, intensification seems likely over the next few days. The HWRF and HMON remain adamant about a powerful hurricane, with minimum barometric pressure forecasts of 948mb and 945mb, respectively. The ECMWF just posted its most bullish run in some time, bottoming Hector out at 960mb in four days or so, and the GFS is only slightly higher at 968mb a day earlier. There are two main questions at this point: when does Hector peak, and at what strength? With consistent shear and ocean temperatures, the main driving factors for intensity will be inner core changes and decreasing mid-level relative humidity values. However, if Hector maintains an insulated core, and especially if it takes on annular characteristics which the environment seems supportive of, this may not matter as much; this is advertised by the ECMWF, which keeps Hector around or under 965mb for the next week at least (the model is still running as of this typing). The SHIPS and LGEM continue to be the weakest of the models, keeping Hector as a strong Category 1 or a Category 2 hurricane on days four and five; however, the SHIPS is slightly higher at these ranges compared to earlier. All told, the updated forecast has been increased to fully commit to the HWRF/HMON solutions, and it has also been slightly increased in the longer range to compensate for recent modelling. A peak intensity of 120kt is assigned between days three and four.
Hector continues its westward trek. The large subtropical ridge to its north is in the process of intensifying, and Hector should begin to lose latitude through 48 hours as a result. By day 3, a large upper-level trough should develop in the northeastern Pacific and erode the ridge, allowing Hector to turn west-northwest. The GFS, which was the northernmost model of the entire suite earlier today, has shifted south at days four and five, bringing models into better agreement. It is still too early to determine how close Hector will track to the Hawaiian Islands, although early guidance suggests residents there should be paying close attention.
FORECAST POSITIONS AND MAX WINDS
INIT 03/0900Z 95 KT 110 MPH
12H 03/1800Z 100 KT 115 MPH
24H 04/0600Z 105 KT 120 MPH
36H 04/1800Z 110 KT 125 MPH
48H 05/0600Z 115 KT 130 MPH
72H 06/0600Z 115 KT 130 MPH
96H 07/0600Z 110 KT 125 MPH
120H 08/0600Z 100 KT 115 MPH