Hurricane John Discussion Number 10
Wiki-Hurricanes Forecast Center
8:00 PM HST Tue Aug 7 2018
Hurricane John's large size is proving to be a challenging obstacle for the hurricane's intensification as various channels of dry subsident air are evident in various locations at varied heights throughout the circulation. Still, the hurricane has managed to put together a more coherent eyewall, and the eye has become more clear on infrared and visible imagery. Microwave data this evening shows the eyewall is complete, but is rather shallow except for disparate locations along the eyewall. However, overall internal core organization is rather steady. SAB estimated a T5.0/90kt current intensity, with UW-CIMSS ADT at T5.3/97kt, though data-T values have been decreasing. SATCON values are at a similar 97 kt. A steady microwave structure coupled with improving infrared organization suggests winds are holding steady but are becoming more homogenous around the hurricane's circulation. Thus, the intensity this advisory has been held at 95 kt.
John continues to move towards the northwest in response to a nearby weakness in the ridge over the Baja California, and not much has changed with the track forecast. Models are in good agreement on an eventual westerly curve as the weakness withers off towards the end of the forecast. Atmospheric conditions remain favorable for intensification with moist air, modest wind shear, and warm ocean waters, but the storm's lanky structure should keep things slow. After some slight intensification, weakening is expected to take place once the storm moves across the tropical/subtropical thermal isotherm.
FORECAST POSITIONS AND MAX WINDS
INIT 08/0300Z 95 KT 110 MPH
12H 08/1200Z 100 KT 115 MPH
24H 09/0000Z 95 KT 110 MPH
36H 09/1200Z 80 KT 90 MPH
48H 10/0000Z 60 KT 70 MPH
72H 11/0000Z 45 KT 50 MPH
96H 12/0000Z 30 KT 40 MPH
120H 13/0000Z 25 KT 30 MPH